IC-NRLF 


RM I  NATION 


\ 


LIBRARY 

OF   THE 

UNIVERSITY  OF  CALIFORNIA 

Received. 
Accessions  No.  &.*£-?/-'?-' Shelf  No. 


& 


TABLES 


FOR  THE 


Determination  of  Common  Minerals 

CHIEFLY  BY  THEIR 

PHYSICAL   PROPERTIES 

WITH  CONFIRMATORY  CHEMICAL  TESTS. 

9 

BY 

W.  O.  CROSBY, 

ASSISTANT  PROFESSOR  OF  MINERALOGY  AND  LITHOLOGY  IN  THE 
MASSACHUSETTS    INSTITUTE  OF  TECHNOLOGY. 


SECOND  EDITION. 


(UITIVBRSIT7 


BOSTON : 

J.  ALLEN  CROSBY, 
1891. 


Copyri 
4* 


yright,  1888, 
4*  ^  £>/2_— 

By  W.  O.  CROSBY. 


PRINTING   OFFICE  OF  THE   PUBLISHER, 
JAMAICA      PLAIN,   BOSTON,    MASS. 


OP  THE 

UHIVBRSIT7 


PREFACE. 

Although  the  published  tables  for  the  determination  of  minerals  are 
very  numerous,  yet  an  experience  of  five  years  in  the  Mineralogical 
Department  of  the  Massachusetts  Institute  of  Technology  and  in  the 
Teachers'  School  of  Science  of  the  Boston  Society  of  Natural  History 
has  convinced  me  that  several  important  features  are  wanting  in 
the  best  tables,  for  the  use  of  beginners  and  general  students,  with 
which  I  am  acquainted.  The  primary  objects  of  any  system  of  de- 
derminative  mineralogy  should  be  :  (i)  to  enable  the  student  to  identify 
certainly  and  easily  such  minerals  as  he  is  likely  to  meet;  and  (2) 
to  cultivate  his  powers  of  observation  and  discrimination,  and  increase 
his  familiarity  with  the  various  species  and  natural  groups  of  minerals. 
The  first  of  these  primary  objects  has  been,  rightly  enough,  the  chief 
aim  of  previous  tables ;  but  it  is  to  be  hoped  that,  as  regards  its  di- 
rect educational  value,  determinative  mineralogy  will  not  always  be, 
as  it  is  now,  far  behind  determinative  or  analytical  botany. 

The  principal  defects  of  the  best  tables  now  in  use,  so  far,  at  least, 
as  the  general  student  is  concerned,  are  that  they  have  too  wide  a 
scope,  embracing  all  or  a  very  large  proportion  of  the  known  species 
of  minerals,  and  that  the  determinations  depend  almost  entirely  upon 
the  chemical  behavior  of  the  species. 

It  is  scarcely  possible  to  overstate  the  enormous  disparity,  as  regards 
their  abundance,  between  the  two  or  three  hundred  common  minerals 
and  the  one  thousand  or  more  rare  species.  The  former  are  found 
abundantly  in  many  localities,  and  in  all  good  collections,  and  are, 
generally  speaking,  the  only  species  the  student  will  meet  or  have  oc- 
casion to  identify ;  while  the  latter  are  very  restricted  in  distribution, 
being  often  known  from  only  a  single  locality,  occuring  for  the  most 
part  in  impure  or  very  minute  specimens,  and  being  inadequately  rep- 
resented even  in  the  largest  and  most  complete  collections. 

The  advantages  of  limiting  determinative  tables  to  the  common  spe- 
cies are  that  they  are  then  far  less  voluminous  and  complicated,  the 
determinations  can  be  made  more  readily  and  accurately,  and  the  use 
of  difficult  or  uncertain  tests  is  avoided.  The  only  disadvantage  is 
that  there  must  often  remain  the  possibility  that  the  specimen  in  hand 
belongs  to  one  of  the  rare  species  not  included  in  the  tables.  But, 
as  already  explained,  this  difficulty  is  very  small ;  and  it  can  not  be 
entirely  obviated  by  the  use  of  the  most  perfect  tables,  since  it  is  prob- 
able that  a  large  proportion,  perhaps  a  majority,  of  the  rare  species 
are  still  unknown  and  unnamed. 


Chemical  or  blowpipe  tests  are  valuable,  since  the  indications  which 
they  afford  are  usually  very  definite  and  precise  ;  and  since  they  direct 
the  student's  attention  particularly  to  the  chemical  composition  and 
behavior  of  the  species  he  is  investigating,  which  is  of  great  im- 
portance. Nevertheless,  there  are  several  good  reasons  why  they  should 
occupy  a  subordinate  place  in  a  system  of  determinative  mineralogy 
intended  for  general  use.  Not  the  least  of  these  is  their  inconvenience, 
since  they  require,  in  the  aggregate,  a  considerable  amount  of  apparatus, 
and  re-agents,  in  other  words,  a  .blowpipe  laboratory.  This  consider- 
ation, and  the  knowledge  of  chemistry  which  the  system  demands, 
practically  restricts  the  instruction  to  high  schools  and  colleges ;  and 
even  then  the  chemical  system  is  not  found  to  be  practicable  in  after  life, 
when  the  student  of  mineralogy  no  longer  has  access  to  the  facilities 
afforded  by  the  school.  Every  teacher  of  blowpipe  analysis  must  have 
noted  and  lamented  the  fact  that,  as  a  rule,  the  elaborate  system  so 
carefully  taught  is  used,  after  the  students  leave  school,  only  by  the 
few  who  become  professional  mineralogists,  chemists  or  miners. 

Perhaps  the  most  serious  objection  to  the  chemical  tables  is  that 
their  use  has  comparatively  little  tendency  to  render  their  aid  unnec- 
essary, by  making  the  student  more  familiar  with  the  external  appear- 
ances of  minerals.  Unquestionably,  determinative  tables  are,  at  the 
best,  a  necessary  evil.  It  were  far  better  to  recognize  minerals  on 
sight,  by  their  structural  and  physical  characters  ;  and,  other  things  being 
equal,  the  preference  should  be  given  to  that  system  of  determination 
which  promises  the  largest  development  of  this  power  in  the  student. 

These  tables  are,  then,  an  attempt  to  determine  about  two  hundred 
minerals  by  their  more  obvious  physical  and  structural  features,  with 
confirmatory  chemical  tests.  The  latter  will  not  usually  be  required  when 
the  specimens  are  pure  and  well  characterized.  But  they  are,  as  a 
rule,  so  simple  and  decisive  that  their  use  is  strongly  recommended 
whenever  convenient  and  the  determination  is  not  otherwise  perfectly 
satisfactory.  Only  those  tests  have  been  selected  requiring  the  min- 
imum of  apparatus,  re-agents  and  previous  chemical  training,  with  a 
view  to  adapting  the  tables  to  the  use  of  common  schools  and  private 
students. 

The  various  properties  of  minerals,  and  all  the  chemical  and  blow- 
pipe tests  referred  to  in  the  tables,  are  fully  explained  in  the  intro- 
duction, which  also  includes  an  outline  of  the  classification  of  minerals  ; 
so  that,  although  this  little  work  is  not  in  any  sense  a  manual  of 
mineralogy,  constant  reference  to  the  more  comprehensive  treatises  is, 
avoided. 

Boston  Society  of  Natural  History, 
Boston,  November  i,   1886. 


INTRODUCTION. 


The  properties  or  natural  characteristics  of  minerals,  by  which  they 
are  known  and  recognized,  may  be  arranged  in  three  classes,  as 
follows  : — 

1.  Properties  relating  to  the  form  and  structure  (crystallization,  etc.) 
of  minerals — morphologic  properties. 

2.  Properties  relating   to    the    action    on    minerals    of  the    various 
physical  forces — -physical  properties. 

3.  Properties  relating  to  the  composition  and  chemical  behavior  of 
minerals — chemical  properties. 

For  the  sake  of  convenience,  and  to  indicate  their  subordinate 
position  in  these  tables,  the  chemical  properties  are  described  last,  al- 
though in  a  systematic  treatise  on  mineralogy  this  class  would  prop- 
erly come  first. 

MORPHOLOGIC  PROPERTIES   OR    CRYSTALLOGRAPHY. 

The  principal  forms  and  structures  of  minerals  are  those  due  to  their 
crystallization ;  but  there  are  other  kinds  that  are  quite  independent 
of  crystallization.  Hence  crystallography  is  only  a  part,  although  the 
main  part,  of  the  general  science  of  the  forms  and  structures  or 
morphology  of  minerals. 

Definition  of  a  Crystal. — A  crystal  is  a  natural  solid  bounded  by  plane 
surfaces  symmetrically  arranged  with  reference  to  certain  imaginary 
lines  or  directions  of  growth  passing  through  its  centre  and  called  the 
axes.  Most  crystals  break  or  cleave  with  great  ease  in  certain  defi- 
nite directions  ;  and  this  geometric  splitting,  or  crystalline  cleavage,  as 
well  as  certain  optical  properties  of  crystals,  proves  that  crystallization 
means  regularity  of  internal  structure  as  well  as  of  external  form. 

Degrees  of  Individualization  of  Crystals. — Crystals  are  the  mineral 
individuals,  and  several  degrees  of  distinctness  and  perfection  of 
crystallization  or  individualization  are  recognized,  as  follows  :  When  the 
crystals  are  distinct  or  separate  and  so  nearly  perfect  that  their  prop- 
er forms  may  be  clearly  recognized,  the  mineral  is  crystallized.  When 
we  have  a  confused  mass  showing  crystal- faces  or  planes  and  cleavage 
planes,  but  no  perfect  crystals  (rock-salt  and  white  marble),  it  is  crys- 
talline or  massive.  When  crystalline  form  and  cleavage  are  both  en- 
tirely wanting  to  the  unaided  eye,  but  the  specimen  exhibits  the  phe- 
nomenon of  double  refraction  when  a  thin  section  is  viewed  by  polarized 
light  (chalcedony),  it  is  cryptocrystalline  or  compact,  \\fhen  mineral 
matter  is  entirely  devoid  of  crystallization  (opal  and  obsidian),  it  is 
-described  as  amorphous  or  wholly  unindividualized. 


Forms  of  Crystals. — This  is  the  most  important  and  at  the  same 
time  the  most  difficult  section  of  crystallography ;  anti  the  student  it- 
particularly  recommended  to  refer  to  a  standard  treatise,  such  as  Dana's 
Text-book  of  Mineralogy.  But  little  more  can  be  attempted  here  than 
an  explanation  of  the  terms  used  in  the  tables.  The  numerous  forms 
of  crystals  are  arranged  in  six  systems,  based  on  the  relative  lengths, 
positions  and  numbers  of  the  axes.  Each  system  has  a  number  as 
well  as  a  name,  and  in  the  tables  they  are  indicated  by  the  Roman 
numerals. 

I.  Isometric  System. — The  simplest  form  in  this  system  is  the 
cube,  with  six  square  sides  or  planes.     Then  comes  the  octahedron  with 
eight  triangular  planes,  the  dodecahedron  with  twelve  rhombic  planes,, 
the  trigonal  trisoctahedron  with  twenty-four  triangular  (trigonal)  planes, 
the  tetragonal  trisoctahedron  with  twenty-four  quadrangular  (tetragonal) 
planes,  the  tetrahexahedron  with  twenty-four  triangular  planes  arranged 
on  the  plan  of  the  cube  instead  of  the  octahedron,  and  lastly  the  hex- 
octahedron  with  forty-eight  planes.     All  of  these  forms,  except  the  cube 
and  dodecahedron,  may   occur  with  only   half  the  planes  developed, 
giving  what  are  called  hemihedral  (half-faced)  forms,  which  may  have 
distinct  names,  the  hemi-octahedron  being  also  called  the  tetrahedron, 
etc.     In  general,  both  the  number  and  arrangement  of  the  planes  are 
quite  clearly  expressed  in  the  crystallographic  names. 

II.  Tetragonal  System. — The  square  or  tetragonal  prism  is  the 
simplest  or  fundamental  form  of  this  system.     There  is  also  an  eight- 
sided  or  ditetragonal  prism.     The  end  planes  of  the  prisms  are  called 
the  basal  planes.     The  remaining  forms  are  the  sqiiare  or  tetragonal 
pyramid,  resembling  the  octahedron  of  the  isometric  system  lengthened 
or  shortened  in  the  direction  of  one  axis,  and  the  ditetragonal  or  eight 
sided    pyramid.     The  crystallographic  pyramid  is  double,  being  equiv- 
alent to  two  geometric  pyramids  placed  together,  base  to  base  ;  and  it 
contains,  in  each  case,  twice   as  many  planes  as  the  name  indicates. 

III.  Hexagonal  System. — In  this  system,  as  the  name  implies, 
the  fundamental  form  is  the  hexagonal  prism.     The  holohedral  forms 
are  strictly  analogous  to  those  of  the  tetragonal  system.     Thus  we  have 
the  hexagonal  and  dihexagonal  prisms,  basal  planes,  and  hexagonal  and 
dihexagonal  pyramids.     The  most  important  of  the  hemihedral  forms 
are  the  hemihexagonal  pyramid  or  rhombohedron ,  a  form  bounded  by 
six  rhombic  planes  and  resembling  an  oblique  cube ;  and    the  hemi- 
dihexagonal  pyramid  or  scalenohedron. 

IV.  Orthorhombic  System. — The  fundamental  form  here  is  the 
ortho  (right),  rhombic  prism,  which  gives  the   name    to    the    system. 
Then  comes  the  right  rectangular  prism,    consisting    of    two    narrow 
planes  called  brachypinacoids  and  two  broad  planes  called  macropina- 
coids.     The  two  end  planes,  as  before,  are  the  basal  planes.     The  eight 


inclined  or  sloping  planes  corresponding  in  position  to  the  orthorhombic 
^rism  planes  make  the  orthorhombic  pyramid ;  while  the  four  inclined 
planes  corresponding  to  the  brachy  and  macro  pinacoids,  respectively, 
are  the  brachy  and  macro  domes. 

V.  Monoclinic  System. — This  system  is  essentially    similar    to 
the  last,  except  that  one  of  the  axial  intersections  is  oblique,  so  that 
the  forms  all  incline  in  one    direction    (monoclinic).     The    prefixes 
of  the  names  pinacoid  and  dome  are    ortho    and    clino,    instead    of 
macro  and  brachy ;  and  we  call  the  prism  and  pyramid    monoclinic, 
instead  of  orthorhombic. 

VI.  Triclinic  System. — The  forms  of  this  system  are  analogous 
to  those  of  the  fourth  and  fifth  systems  ;  but  are  easily  distinguished 
by  the  fact  that  the  angles  are  all  oblique. 

When  all  the  planes  on  a  crystal  are  of  one  kind,  it  is  described 
as  a  simple  form  and  given  one  crystallographic  name.  But  when 
they  are  of  two  or  more  kinds  it  is  called  a  compound  form,  and 
requires  for  its  accurate  description  as  many  crystallographic  names 
as  there  are  kinds  of  planes.  Thus,  on  the  ordinary  crystal  of  quartz 
there  are  two  kinds  of  planes,  and  we  describe  it  as  a  combination 
of  the  hexagonal  prism  and  the  hexagonal  pyramid. 

These  compound  forms  must  be  carefully  distinguished  from  the 
compound  or  (twin}  crystals.  The  quartz  crystal,  although  described 
as  a  compound  form,  because  there  are  two  forms  or  kinds  of  planes, 
is  a  single,  simple  crystal.  But  if  two  such  crystals  should  grow 
together  in  a  regular  manner,  the  result  would  be  a  double  or  twin 
crystal. 

Stntctures  of  Crystals. — The  only  topic  that  need  be  noticed  under 
this  head  is  the  regular  splitting  exhibited  by  most  crystals — 

Crystalline  Cleavage,  which  is  scarcely  less  important  to  the 
student  of  determinative  mineralogy  than  the  external  forms  of  crystals. 

Amorphous  bodies,  such  as  glass  and  opal,  being  essentially  homoge- 
neous, possess  no  planes  of  least  cohesion,  but  are  equally  strong  in 
all  directions.  Consequently,  when  broken  they  yield  fragments  of 
very  irregular  forms.  But  the  regular  molecular  structure  of  crystals, 
as  already  stated,  is  usually  indicated  by  definite  directions  of  easy 
splitting  or  cleavage ;  so  that  the  fragments  present  on  one  or  more 
sides  flat  lustrous  surfaces.  Cleavage  is  independent  of  hardness, 
being  almost  equally  perfect  in  diamond  and  talc,  the  hardest  and 
softest  of  minerals.  The  cleavage  directions  or  planes  are  always 
parrallel  to  some  actually  occuring,  or  to  some  possible,  external 
planes  of  the  crystal ;  and  are  usually  limited  to  the  simpler  forms  in 
each  system.  Consequently  it  is  often  possible  to  determine  all  the 
more  important  features .  of  the  crystallization  of  a  mineral  from  the 
examination  of  small  cleavage  fragments. 


There  are  different  degrees  of  cleavage.  When  the  mineral  splits 
very  easily,  yielding  smooth  and  -brilliant  surfaces,  like  mica,  the 
cleavage  is  perfect  or  eminent ;  and  the  inferior  degrees  are  described 
as  distinct,  indistinct  or  imperfect,  interrupted,  in  traces,  difficult,  etc. 

The  different  cleavage  directions  are  named  after  the  external 
planes  of  the  crystals  with  which  they  are  parallel.  Thus,  in  the 
isometric  system  we  have  cubic,  octahedral  and  dodecahedral  cleav- 
ages. The  principal  kinds  of  cleavage  in  the  other  systems  are  the 
prismatic,  basal  and  pyramidal,  besides  the  rhombohedral  cleavage  of 
the  third  system  and  the  pinacoidal  cleavages  of  the  fourth,  fifth  and 
sixth  systems. 

Forms  and  Structures  of  Mineral  Aggregates. — Minerals  frequently 
occur  in  masses  having  a  more  or  less  definite  external  form  and  in- 
ternal structure,  the  form  and  structure  of  which  are  not  due  wholly, 
if  at  all,  to  crystallization,  /.  e.,  to  a  regular  geometric  arrangement 
of  the  mineral  molecules,  but  are  the  product,  in  part  at  least,  of 
forces  different  from  those  by  which  crystals  are  made.  These 
masses  or  aggregates  are  usually  uncrystalline,  and  are  never  single 
crystals  or  regular  compounds  of  crystals. 

External  Forms  of  Mineral  Masses. — When  mineral  matter 
is  deposited  in  parallel  layers  on  uneven  surfaces,  the  upper  surface  of 
the  deposit,  like  snow  that  has  fallen  on  uneven  ground,  presents 
smoothly  rounded  hummocks  or  elevations.  If  these  are  small  and 
somewhat  graperlike  in  outline,  the  form  is  described  as  botryoidaL 
When  the  rounded  prominences  are  larger,  the  form  is  called 
mammillary. 

Closely  related  to  these  deposition  forms  are  those  produced  when 
water  holding  mineral  matter  in  solution  falls,  drop  by  drop,  from  an 
overhanging  surface  of  rock.  The  pendant  cone  or  column  thus  pro- 
duced is  called  a  stalactite,  and  the  form  is  described  as  stalactitic. 
The  low  mound  or  layer  made  by  the  water  dripping  from  the  point 
of  a  stalactite  upon  the  rocky  floor  below  is  called  a  stalagmite,  the 
adjective  term  being  stalagmitic.  The  porous  deposits  formed  when 
reeds,  grass,  moss,  and  other  kinds  of  vegetation  are  encrusted  by 
mineral  solutions  is  called  a  tufa,  and  its  form  and  structure  are 
described  as  tufaceous. 

A  round  mass  or  nodule  produced  by  the  segregation  of  mineral 
matter  in  the  body  of  a  rock  is  called  a  concretion,  the  form  being 
concretionary.  If  the  concretions  are  small,  about  like  peas,  the 
form  is  called  pisolitic ;  but  if  they  are  as  small  as  mustard  seed  it  is 
oolitic.  Hollow  concretions  are  called  geodes.  The  amygdaloidal 
(almond-like)  form  results  from  the  deposition  of  mineral  matter  in 
the  vesicles  or  steam-holes  of  lava.  In  the  stains  of  iron  and  man- 
ganese oxides  known  as  dendrite,  in  moss  agate,  often  in  native 


7 

copper,  and  on  a  frosted  window  pane,  we  have  forms  which  are 
called  dendritic,  arborescent  and  mossy.  These  are  usually  more  or 
less  dependent  upon  the  crystallization ;  and  from  these  we  pass  easily 
to  the  reticulated  and  plumose  forms.  The  native  metals,  especially, 
occur  in  wire-like  or  thread-like  shapes,  and  are  described  z$  filiform 
or  capillary,  while  slender,  needle-like  crystals  are  acicular.  When 
a  surface  is  thickly  set  with  crystals  of  uniform  size,  they  are  described 
as  implanted  crystals ;  and  when  the  implanted  crystals  are  very  small, 
the  form  is  called  drusy. 

Internal  Structures  of  Mineral  Masses. — We  have,  first,  the 
different  kinds  of  granular  structure.  The  grains  are  usually  merely 
small,  imperfect  crystals,  and  there  is  a  perfect  gradation  from  the 
most  coarsely  to  the  most  finely  granular  kinds.  When  the  grains 
become  invisible  to  the  naked  eye,  the  structure  is  compact  or  impalpa- 
ble ;  and  when  no  trace  of  a  granular  structure  can  be  detected,  even 
with  the  microscope,  the  mineral  is  glassy  or  vitreous.  In  this  state 
it  may  be  crystalline,  like  vitreous  quartz,  or  amorphous,  like  obsidian. 

The  lamellar  structures  come  next  in  importance.  We  properly 
distinguish  at  the  outset  those  masses  in  which  the  lamination  is 
entirely  independent  of  crystallization,  from  those  in  which  it  is  not. 
In  the  first  class  this  structure  is  commonly  described  as  banded,  and 
in  the  second  as  foliated.  The  banded  structure  occurs  commonly 
with  the  botryoidal,  stalactitic,  stalagmitic  and  geoditic  forms,  and  the 
layers  may  be  straight  (plane)  or  curved  and  concentric.  The/<?//'- 
ated  structure,  on  the  other  hand,  is  simply  an  easy  splitting  in  parallel 
planes  due  to  very  perfect  cleavage  in  one  direction.  The  cleavage 
is  usually  basal ;  and  foliation  has  its  best  development  in  the  micas 
and  allied  minerals. 

The  fibrous  structure  is  the  third  principal  kind.  It  also  depends 
upon  the  crystallization ;  for,  as  we  may  usually  regard  the  granular 
masses  as  aggregates  of  short,  thick  crystals ;  the  foliated  masses  as 
aggregates  of  flat,  tabular  crystals ;  so  the  fibrous  masses  may  be  re- 
garded as  examples  of  very  slender,  attenuated  crystallization — pris- 
matic crystallization  carried  to  an  extreme.  When  the  fibres  are 
large  and  distinct  the  structure  is  called  columnar  or  bladed. 

In  the  tables,  not  only  the  system  in  which  the  mineral  crystallizes, 
but  any  marked  habit  of  crystallization,  and  it  is  more  characteristic 
uncrystalline  or  massive  forms  are  briefly  indicated. 

The  habit  of  crystallization  is  called  distinctly  prismatic  or  distinctly 
tabular  etc.,  only  when  the  development  of  these  forms  is  very 
marked,  the  prisms,  for  example,  being  several  or  many  times  longer 
than  thick. 


PHYSICAL  PROPERTIES. 

The  topics  to  be  considered  here  are  those  characteristics  of  min- 
erals depending  upon  their  relations  to  the  physical  forces,  such  as. 
cohesion,  elasticity,  light,  heat,  electricity,  etc. 

Properties  relating  to  Cohesion  and  Elasticity. —  Cohesion  is  the 
resistance  which  any  body  offers  to  a  force  tending  to  separate  its 
molecules  or  particles,  either  by  breaking  or  abrasion.  The  principal 
properties  relating  to  this  force  are  cleavage,  fracture,  and  hardness. 

Elasticity,  on  the  other  hand,  is  the  force  which  tends  to  bring 
the  molecules  of  a  body  back  into  their  original  positions  when  they 
have  been  disturbed.  Upon  elasticity  depends,  for  the  most  part, 
the  different  degrees  of  tenacity  possessed  by  minerals. 

Cleavage  and  Fracture. — When  minerals  are  broken,  if  the 
divisions  are  determined  in  direction  and  character  by  the  crystalliza- 
tion, yielding  smooth,  plane  surfaces  parallel  to  the  external  planes 
of  the  crystal,  the  breaking  is  called  cleavage ;  but  if  the  divisions 
are  independent  of  the  crystalline  form,  and  usually  more  or  less 
irregular,  the  breaking  is  called  fracture. 

Although  cleavage  planes  are  directions  in  crystals  along  which  the 
molecules  separate  readily,  and  cleavage  is,  in  this  respect,  evidently 
related  to  cohesion,  yet  it  is  far  more  important  as  a  manifestation  of 
the  molecular  structure  of  crystals ;  and  its  characteristics  have,  there- 
fore, been  described  in  the  preceding  section  (see  page  5).  When 
the  cleavage  is  perfect,  true  fracture  is  difficult  to  obtain,  on  account 
of  the  strong  tendency  of  the  breaking  to  follow  the  directions  of 
least  resistance,  /.  e.,  the  cleavage  directions.  The  most  important 
kinds  of  fracture  are :  the  conchoidal,  the  mineral  breaking  with 
curving  concavities  resembling  the  valve  of  a  shell ;  the  even,  when 
the  surface  of  the  fracture  is  approximately  smooth ;  the  uneven ;  the 
earthy,  breaking  like  clay  or  chalk;  and  the  hackly,  splintery,  etc.  In 
the  tables,  the  fracture  is  given  only  where  the  cleavage  is  very  im- 
perfect or  entirely  wanting. 

Hardness. — The  hardness  of  a  mineral  is  the  resistance  which  it 
offers  to  abrasion.  Hardness,  however,  is  a  purely  relative  term, 
and  hence  mineralogists  have  found  it  necessary  to  select  certain 
minerals  to  be  used  as  a  standard  of  comparison  for  all  others.  This 
scale  of  hardness  consists  of  ten  minerals  showing  a  regular  gradation 
in  hardness  from  talc,  which  is  one  of  the  softest  of  minerals,  to- 
diamond,  the  hardest  of  all  minerals,  as  follows  : — 

1.  Talc.  (6.  Orthoclase. 

2.  Gypsum.  -7.  Quartz. 

3.  Calcite.  8.  Topaz. 
Fluorite.  9.  Corundum. 

.  Apatite.  10.  Diamond. 


Arranged  in  this  order,  each  member  of  the  scale  is  harder  than 
(/.  e.,  will  scratch)  all  that  come  before  it,  and  softer  than  (/.  e.y 
is  scratched  by)  all  that  come  after  it.  The  degree  of  hardness  pos- 
sessed by  any  mineral  may  be  determined  by  direct  comparison  with 
the  scale,  and  is  expressed  by  the  number,  rather  than  the  name,  of 
the  member  of  the  scale  to  which  it  corresponds.  Thus,  if  it  does 
not  scratch  orthoclase,  and  is  not  distinctly  scratched  by  orthoclase, 
its  hardness  is  6.  If  it  scratches  fluorite,  but  is  scratched  by  apatite, 
its  hardness  is  between  4  and  5  ;  and  it  is  possible,  by  making  the 
test  carefully,  to  determine  whether  it  is  about  4.25,  4.5  or  4.75. 

Although  it  is  important  that  the  student  should  be  acquainted 
with  the  scale  of  hardness,  and  understand  how  to  use  it,  it  is  not 
essential  for  the  determination  of  common  minerals.  Very  few  com- 
mon minerals  have  hardness  above  7 ;  and  hence  for  all  ordinary 
purposes  the  thumb-nail,  a  knife  or  file  and  a  piece  of  quartz  are 
sufficient.  In  the  column  marked  "H,"  in  the  tables,  the  exact,  or 
where  variable  the  average,  hardness  of  each  species  is  given,  so  that 
careful  comparisons  may  be  made  when  desired.  But  an  examination 
of  the  analytical  key  on  the  left  margin  of  each  table,  or  of  the  general 
classification  of  the  tables,  will  show  that  the  determinations  are  based 
upon  a  scale  of  hardness  embracing  only  five  degrees,  as  follows  : — 

1.  Very  soft   (below    2.5)  ;  can  be  scratched  with  the    nail,  or    very 

easily  with  the  knife. 

2.  Soft  (2.5-4)  ;  cannot  be  scratched  with  the  nail,  but  easily  scratched 

with  the  knife. 

3.  Hard   (4-6)  ;  can  be  be  scratched  with  the  knife,  but  not  easily. 

4.  Very  hard   (6-7)  ;  cannot  be  scratched  distinctly  with    the    knife, 

but  is  scratched  by  quartz. 

5.  Adamantine   (above   7)  ;  cannot  be  scratched  by  quartz. 

The  figures  in  the  parentheses  give  the  corresponding  degrees  of  the 
regular  scale. 

The  great  advantage  of  this  scale  is  its  convenience,  combined  with 
a  reasonable  degree  of  accuracy.  The  adamantine  minerals,  or  those 
having  hardness  above  7,  are  all  found  in  one  small  group  at  the 
very  end  of  the  tables.  Hence,  in  nearly  all  cases  the  quartz  will 
not  be  required,  the  knife  and  thumb-nail  being  sufficient ;  and  a 
little  practice  will  enable  the  student  to  determine  whether  a  mineral 
which  can  be  scratched  with  the  knife  scratches  easily  or  with  difficulty. 
The  doubtful  or  variable  minerals  are  repeated  in  all  the  sections  of 
the  tables  to  which  students  would  be  likely  to  assign  them.  It 
is  important,  however,  to  note  that  beginners  usually  overestimate  the 
hardness  of  minerals;  and  that  a  sharp  angle  will  usually  slightly 
scratch  a  flat  surface  of  the  same  mineral.  The  student  will  also 
learn  to  make  allowance  for  foreign  substances  or  impurities. 


IO 


Tenacity. — All  solid  minerals  may  be  classed  as  either  brittle  or 
flexible.  Brittle  minerals,  to  which  class  the  majority  belong,  are  those 
whose  forms  can  not  be  sensibly  distorted  without  rupture.  The  de- 
gree of  cohesion,  however,  varies  greatly ;  some  brittle  minerals  being 
very  rigid  or  strong  and  breaking  with  great  difficulty,  like  corundum ; 
while  in  the  typical  brittle  minerals,  such  as  quartz  and  calcite,  the 
cohesion  is  less  and  a  moderate  blow  suffices  to  break  them.  But 
the  minimum  cohesion  is  found  in  the  friable  minerals,  which  are  at 
once  very  brittle  and  very  easily  broken.  Brittle  minerals,  in  other 
words,  are  those  which  break  suddenly  under  a  blow,  and  whether  the 
tlow  needs  be  light  or  heavy  is  immaterial. 

Flexible  minerals,  on  the  other  hand,  are  those  whose  forms  can  be 
sensibly  distorted  without  rupture.  All  flexible  minerals  are  also  sectile, 
i.  e.,  can  be  cut  without  breaking  or  crumbling.  All  brittle  minerals 
are  elastic,  and  the  elastic  flexible  minerals,  such  as  mica,  are  those 
possessing  the  least  flexibility  in  pieces  of  ordinary  thickness,  consti- 
tuting an  intermediate  class  between  the  brittle  and  flexible  minerals. 
The  typical  flexible  minerals  are  malleable  and  ductile  as  well  as 
sectile.  As  in  the  brittle  class,  the  degree  of  cohesion  varies  greatly. 
This  is  seen  by  comparing  iron  and  copper  with  gypsum  and  talc. 

Properties  Relating  to  Mass  and  Volume. — All  that  we  have  to  con- 
sider here  is  the  ratio  of  the  mass  and  volume  in  minerals,  /.  e.,  the 

Specific  Gravity. — By  the  specific  gravity  of  a  mineral  we  mean 
its  weight  compared  with  the  weight  of  an  equal  volume  of  water. 
Although  this  property  is  quite  as  fundamental  and  constant  as  hard- 
ness, it  is  less  useful  in  the  determination  of  minerals,  on  account  of 
the  greater  difficulty  of  measuring  it  with  the  same  degree  of  ac- 
curacy. The  specific  gravity  of  solid  bodies  is  usually  determined  as 
follows  : — The  specimen  is  first  weighed  carefully  on  a  good  balance  ; 
it  is  then  suspended  from  one  pan  of  the  balance  by  a  thread  or  fine 
wire  in  a  glass  of  water,  and  while  hanging  freely  and  completely  im- 
mersed, its  weight  is  taken  again.  The  second  weight  is  subtracted 
from  the  first.  The  difference,  or  loss  by  immersion,  is  the  weight 
of  a  volume  of  water  equal  to  that  of  the  specimen ;  and  by  dividing 
this  weight  into  the  first  weight  of  the  specimen,  the  desired  ratio  is 
obtained.  For  example,  a  piece  of  quartz  weighs  25  grains  in  air,  and 
15.57  grains  in  water.  25 — 15.57=9.43  grains,  the  weight  of  an  equal 
volume  of  water.  25—9.43=2.65,  the  specific  gravity  of  quartz. 

Minerals  exhibit  a  wide  range  in  specific  gravity,  from  petroleum, 
which  floats  on  water,  to  gold,  which  is  nearly  twenty  times  heavier 
than  water.  Very  few  minerals,  however,  are  heavier  than  iron (7. 5) 
and  still  fewer  are  lighter  than  sulphur  (2),  the  great  majority  falling 
between  2.5  and  5.  But,  notwithstanding  this  narrow  range,  the  stu- 
dent can,  with  practice,  learn,  by  merely  lifting  specimens  to  estimate 


II 


the  specific  gravity  accurately  enough  to  make  it  a  very  valuable  aid 
in  the  determination  of  many  minerals.  This  property  is  relied  upon 
to  some  extent,  in  the  analytical  key  of  the  tables,  for  distinguishing 
groups  of  minerals.  The  caution  with  regard  to  impurities,  given  in 
the  preceding  section,  might  be  repeated  with  additional  emphasis  here. 

Properties  Relating  to  Light. — On  account  of  their  comparatively  su- 
perficial nature  and  the  consequent  ease  with  which  they  may  be  ascer- 
tained, the  optical  properties  play  a  very  important  part  in  determin- 
ative mineralogy. 

Lustre. — By  the  lustre  or  glance  of  a  mineral  is  meant  the  quantity 
and  quality  of  light  reflected  by  it,  as  determined  by  the  character 
or  minute  structure  of  its  surface.  Variations  in  the  nature  of  the 
reflecting  surface  produce  different  kinds  of  lustre ;  and  variations  in 
the  quantity  of  light  reflected,  /.  e.,  in  the  polish  of  the  surface,  pro- 
duce different  degrees  of  lustre. 

The  two  principal  kinds  of  lustre  are  the  metallic  and  non-metallic. 
The  metallic  lustre  is  the  lustre  of  all  true  metals,  such  as  silver,  copper,, 
etc.,  and  of  most  minerals  in  which  metallic  elements  predominate. 
When  the  lustre  is  not  distinctly  or  perfectly  metallic,  it  is  called 
sub- metallic.  The  adamantine  lustre  is  intermediate  between  the  metal- 
lic and  non-metallic  lustres.  It  is  well  shown  in  but  few  minerals, 
the  diamond  being  the  most  perfect  example. 

Most  of  the  minerals  in  which  the  non-metallic  elements  predomi- 
nate have  a  non-metallic  lustre.  This  is  by  far  the  most  common 
lustre,  only  about  one-fifth  of  the  known  minerals  which  have  a 
distinct  lustre  being  either  metallic  or  adamantine.  The  non-metallic 
lustre  embraces  several  varieties,  which  are  named  in  the  order  of 
their  importance  : — 

The  vitreous  is  the  lustre  of  glass,  and  of  all  minerals  similar  to  glass 
in  appearance,  such  as  quartz,  calcite,  etc.  The  resinous  lustre  is  seen  in 
resins,  of  which  the  native  mineral  copalite  is  an  example ;  it  is  also 
well  exhibited  in  sulphur  and  sphalerite.  The  pearly  lustre,  /.  e.,  the 
lustre  of  pearl,  is  well  shown  only  in  minerals  having  a  foliated  or 
scaly  structure,  in  other  words,  very  perfect  cleavage  in  one  direction, 
such  as  talc,  mica  and  gypsum.  The  silky  or  satiny  lustre,  like  the 
pearly,  is  determined  by  the  structure,  being  observed  only  in  finely 
fibrous  minerals.  Fibrous  gypsum  or  satin-spar  is  the  best  illustration, 
although  fibrous  calcite,  serpentine,  malachite,  asbestus,  etc.,  are 
nearly  as  good.  The  greasy  and  waxy  lustres  are  most  common  in 
certain  amorphous  minerals,  such  as  serpentine. 

The  degrees  of  lustre  are  expressed  as  follows  : — 

The  lustre  is  splendent  when  the  surface  reflects  brilliantly,  giving 
well  defined  images.  It  is  shining  when  the  reflected  image  is  not 
well  defined.  When  there  is  a  general  reflection  from  the  surface,  but. 


12 

no  recognizable  image,  the  lustre  is  glistening.  If  the  reflection  is 
very  imperfect,  and  chiefly  from  minute  points,  the  lustre  is  glimmer- 
ing. A  mineral  is  described  as  dull,  when  there  is  a  complete  ab- 
sence of  lustre,  /.  e.,  when  no  light  is  regularly  reflected,  as  in  earthy 
minerals. 

In  using  these  tables,  or  any  determinative  system,  it  is  a  matter  of 
the  first  importance  to  be  able  to  recognize  the  different  kinds  of  lustre, 
and  especially  to  distinguish  the  two  principal  kinds,  metallic  and 
non-metallic.  This  is  the  first  question  to  be  answered  with  every 
species.  One  aid  to  answering  it  correctly  is  found  in  the  perfect 
opacity  of  all  metallic  minerals.  If  the  finest  splinter  or  the  thinnest 
scale  of  the  mineral  in  hand  appears  in  the  slightest  degree  translucent, 
when  held  up  to  the  light,  it  cannot  be  metallic.  But  the  converse 
statement  is  not  always  true,  since  some  non- metallic  minerals  will  ap- 
pear quite  opaque,  except  in  the  excessively  thin  sections  prepared 
with  considerable  labor  for  microscopic  examination.  Metallic  min- 
erals, again,  never  grind  to  an  earthy  (chalk-like)  powder,  but  when 
carefully  examined  the  powder  sparkles,  the  mineral  showing  its  me- 
tallic shine  or  glance  in  the  smallest  particles. 

The  darker  colored  and  nearly  opaque  non-metallic  minerals  are 
among  those  most  likely  to  be  referred  to  the  wrong  lustre  ;  and  many 
of  these,  as  well  as  the  most  of  the  sub-metallic,  adamantine  and  dull 
species  have,  in  consequence,  been  placed  in  both  divisions  of  the 
tables. 

Diaphaneity. — The  light  transmitted  by  minerals  varies  in  amount 
within  wide  limits  ;  or,  in  other  wrords,  of  the  light  received,  and  not 
reflected,  more  or  less  may  be  absorbed.  The  following  degrees  of 
of  diaphaneity  are  usually  recognized  : — 

Transparent,  when  the  outline  of  an  object  seen  through  the  mineral 
is  perfectly  distinct.  Sub  transparent  or  semitransparent,  when  objects 
are  seen  but  the  outlines  are  not  distinct.  Translucent,  when  light 
is  transmitted  but  objects  are  not  seen.  Stib  translucent  or  semitrans- 
lucent,  when  merely  the  edges  of  the  specimen  transmit  light  or  are 
translucent.  Opaque,  when  the  mineral  transmits  no  light  in  ordinary 
specimens. 

The  diaphaneity  is  of  very  little  value  in  the  determination  of  min- 
erals, except  as  an  aid  in  distinguishing  the  metallic  and  non-metallic 
lustres ;  for  it  is  exceedingly  variable  and  inconstant,  the  same  species, 
or  even  the  same  specimen,  often  showing  every  degree  from  trans- 
parent to  opaque.  No  other  property  of  non-metallic  minerals  is 
affected  in  an  equal  degree  by  slight  impurities  and  imperfections. 
In  fact,  if  all  mineral  bodies  were  perfectly  pure  and  homogeneous 
we  should  probably  find  that  the  metallic  species  are  all  opaque,  and 
the  non-metallic  species  are  all  transparent. 


'3 

Color. — The  color  of  a  mineral  is  a  measure  of  its  power  of  absorb- 
ing different  portions  of  the  light  that  passes  through  it  or  falls  on  its 
surface.  If  no  light  is  absorbed,  or,  more  correctly,  if  all  the  rays  of 
the  spectrum  are  absorbed  equally,  the  color  is  white.  If  the  red 
rays  are  absorbed,  the  color  is  green,  and  so  on.  The  color  is  always 
a  mixture  of  the  rays  that  are  not  absorbed. 

The  colors  of  metallic  minerals  are  usually  constant  and  afford  im- 
portant aid  in  distinguishing  species  ;  and  the  same  is  true  of  a  few  of 
the  non-metallic  minerals.  The  great  majority  of  the  non-metallic 
species,  however,  would  be  white  if  perfectly  pure ;  and  since  the 
actual  colors  depend  upon  the  kind  and  quantity  of  impurity  present, 
they  are  extremely  variable. 

The  different  varieties  of  color  in  both  metallic  and  non-metallic 
minerals  are  easily  recognized ;  but  a  far  more  important  distinction 
is  that  between  essential  and  non-essential  colors.  By  the  essential  col- 
or in  any  case  is  meant  the  color  of  the  mineral  itself  in  its  purest 
state  and  in  the  finest  particles.  The  non-essential  colors,  on  the 
other  hand,  are  chiefly  the  colors  of  the  impurities  contained  in  the 
minerals ;  although  appearing  in  some  cases  to  be  due  to  the  molec- 
ular structure.  The  essential  color  is  known  as  the  streak.  Metallic 
minerals,  which  are  always  opaque,  usually  have  essential  colors,  the 
color  of  the  solid  mineral  and  the  powder  being  exactly  or  nearly  the 
same.  But  non-metallic  minerals,  which  are  always  somewhat  di- 
aphanous, usually  have  non-essential  colors  when  not  white,  the  color 
of  the  powder  being  white  or  gray  regardless  of  the  color  of  the 
solid  mineral.  The  explanation  is  this  :  In  opaque  minerals  we  can 
only  see  the  impurity  immediately  on  the  surface,  and  this  is,  as  a 
rule,  not  sufficient  to  affect  the  color.  But  in  diaphanous  minerals 
we  look  into  the  specimen,  and  see  impurity  below  the  surface ;  and 
thus  bring  into  view,  in  many  cases,  sufficient  impurity  so  that  its 
color  drowns  that  of  the  pure  mineral.  To  prove  this  we  have  only 
to  take  any  mineral  (serpentine  is  a  good  example)  having  a  non- 
essential  color  and  make  it  opaque  by  pulverizing  it  or  abrading  its 
surface.  The  non-essential  color,  the  color  of  the  impurity,  immediate- 
ly disappears  just  as  water  yellow  with  suspended  clay  becomes  white 
when  beaten  into  foam  and  thus  made  opaque.  The  essential  color 
of  a  mineral,  or  the  color  of  its  powder,  is  called  the  streak  of  the 
mineral  because  the  powder  is  most  easily  obtained  by  scratching  the 
surface  of  the  mineral  and  thereby  pulverizing  a  minute  portion  of  it. 
A  still  better  method  of  observing  the  streak  of  all  but  adamantine 
minerals  is  to  rub  the  specimen  on  an  unpolished  surface  of  white 
porcelain  or  Arkansas  stone.  The  streak  of  very  soft  minerals  is  easily 
obtained  by  marking  on  paper,  the  lead-pencil  mark  being  the  streak 
of  graphite.  Very  hard  minerals  must  be  pulverized  in  a  mortar. 


14 

Any  merely  superficial  color,  or  color  due  to .  exposure  to  the  air 
or  weather,  is  called  tarnish.  A  mineral  is  described  as  tarnished 
when  the  surface  color  is  different  from  that  on  a  fresh  fracture.  The 
tarnish  is  often  irised  or  marked  by  various  prismatic  colors,  which 
are  explained  as  due  to  interference  of  light  caused  by  a  film  cover- 
ing the  mineral.  This  superficial  film  or  layer  may  be  the  result  of 
oxidation  or  other  alteration  of  the  mineral  itself,  or  it  may  be  a  thin 
incrustation  of  some  foreign  substance. 

Properties  relating  to  Heat  and  Magnetism. — Under  the  head  of  heat, 
mineralogists  investigate  chiefly  the  expansion  and  contraction  of  min- 
erals, their  power  of  absorbing,  conducting  and  radiating  heat,  and 
their  fusibility. 

Fusibility. — This  is  the  most  important  of  these  properties  and  the 
only  one  that  need  be  considered  here.  It  is  hardly  practicable  to 
determine  with  a  thermometer  the  melting  temperature  of  minerals, 
and  the  exact  temperature  of  fusion  is  known  for  only  a  few  species ; 
but  mineralogists  are  usually  satisfied  with  knowing  the  relative  fusing 
points  of  the  different  species.  The  relative  fusibility  is  determined 
by  comparison  with  six  species  which  have  been  chosen  as  a  scale  of 
fusibility.  These,  beginning  with  the  most  readily  fusible,  are  : — 
i.  Stibnite ;  2.  Natrolite ;  3.  Garnet;  4.  Actinolite ;  5.  Orthoclase ; 
6.  Bronzite  ;  and  we  may  add  7.  Quartz.  The  fusibility  of  a  mineral  is 
determined  by  heating  a  fine  splinter  or  fragment  in  the  forceps  or 
on  charcoal  with  the  oxidizing  blowpipe  flame.  If  it  fuses  as  readily 
as  natrolite,  it  is  2,  if,  like  quartz,  it  cannot  be  even  rounded  on  the 
thinnest  edges,  it  is  7,  and  so  on. 

It  is  very  important  that  the  fusibility  should  be  tested  with  very  fine 
splinters  or  scales.  When  this  precaution  is  observed,  stibnite  and 
natrolite  are  readily  melted  to  liquid  globules,  and  garnet  with  a 
stronger  heat ;  but  with  actinolite,  and  still  more  with  orthoclase  and 
bronzite,  the  evidence  of  fusion  is  the  rounding  of  the  sharp  edges 
of  the  splinters.  A  mere  swelling  up  or  intumescence  of  a  mineral 
should  not  be  mistaken  for  fusion. 

Magnetism. — But  few  minerals  are  sensibly  affected  by  an  ordi- 
nary magnet ;  and  these  are  the  species  containing  the  largest  propor- 
tions of  the  strongly  magnetic  element — iron.  The  degree  of  mag- 
netism is  usually  proportional  to  the  percentage  of  iron,  being 
greater  in  magnetite  than  in  any  other  mineral  except  pure  iron. 
Where  the  magnetism  is  weak,  it  can  only  be- detected  by  first  finely 
pulverizing  the  mineral. 

Properties  Relating  to  the  Action  of  Minerals  on  the  Senses. — These 
properties  are  of  little  importance,  except  with  a  few  species. 

Touch  or  Feel. — This  is  described  as  meagre  (chalk,  clay,  etc.), 
harsh,  rough,  smooth,  unctuous  and  greasy. 


Taste. — A  few  minerals,  being  readily  soluble,  have  a  distinct 
taste.  The  principal  kinds  of  taste  mentioned  are  the  astringent, 
cooling,  sour,  bitter,  saline  and  alkaline. 

Odor  or  Smell. — Solid  minerals  are  usually  devoid  of  odor  unless 
subjected  to  some  special  treatment,  as  heating,  rubbing,  moistening, 
etc.  The  principal  kinds  of  odor  are  the  sulphtirous,  arsenical,  argil- 
laceous and  fetid. 

CHEMICAL   PROPERTIES. 

What  we  have  to  consider  here,  chiefly,  is  the  characteristic  chem- 
ical behavior  of  the  common  minerals,  and  especially  of  their  prin- 
cipal constituent  elements.  A  systematic  account  of  the  composition 
and  chemical  relations  of  minerals  would  be  out  of  place  in  a  work 
of  this  kind ;  but  there  is  one  general  principle  of  such  fundamental 
importance  in  determinative  mineralogy  as  to  demand  the  attention  of 
the  student  at  the  very  outset.  This  is  the  relation  of  the  composition 
to  the  physical  properties  of  minerals.  The  comparison  of  almost  any 
mineral  with  the  chemical  elements  of  which  it  is  composed  shows 
that  the  properties  of  minerals  are  often  very  distinct  from  those  of 
their  constituent  elements.  Thus,  the  common  mineral  pyrite  is  com- 
posed of  sulphur  and  iron,  and  in  its  general  aspect  it  resembles 
neither  of  these  elements ;  but  a  closer  comparison  shows  that  most 
of  its  properties  may  be  observed  in  them ;  for  it  is  yellow  and  brittle 
like  sulphur,  and  metallic,  hard  and  heavy  like  iron.  Its  specific 
gravity  is  almost  an  average  of  that  of  the  two  elements.  In  general, 
the  contrast  between  minerals  and  their  component  elements  is  more 
strongly  marked  with  the  comparatively  superficial  properties,  like 
color,  than  with  the  more  fundamental  properties,  such  as  form, 
density,  lustre,  etc.  The  latter  are,  in  a  very  large  degree,  the 
average  of  the  properties  of  the  elements.  Thus  the  minerals  in  which 
heavy,  metallic  elements  predominate,  such  as  galenite,  etc.,  are  them- 
selves heavy  and  have  usually  a  metallic  lustre  ;  while  minerals  composed 
chiefly  of  light,  non-metallic  elements,  such  as  quartz,  etc.,  are  char- 
acterized by  a  low  specific  gravity  and  non-metallic  lustre.  In  ac- 
cordance with  this  principle,  we  find  that  only  those  minerals  are 
magnetic  which  are  richest  in  iron,  the  magnetism  increasing  with  the 
percentage  of  iron ;  and  that,  water  being  one  of  the  lightest  and  softest 
of  mineral-constituents,  the  hydrous  species  are  lighter  and  softer  than 
anhydrous  species  of  otherwise  similar  composition. 

General  BloTvpipe  and  Chemical  Tests  : — Certain  standard  tests  recur 
so  frequently  in  the  tables  that  the  student  is  recommended  to  acquire 
some  familiarity  with  the  modus  operandi  of  each,  and  the  general 
reactions  which  it  yields,  before  proceeding  to  the  more  special 
tests  for  the  indentification  of  the  particular  constituents  of  minerals. 


i6 

Heating  in  the  Closed  Tube. — The  mineral  should  be  in  the 
form  of  powder  or  fine  grains ;  and  the  bulk  of  a  kernel  of  wheat 
will  be  sufficient  in  most  cases.  This  is  placed  in  the  bottom  of  a 
hard  glass  tube  three  inches  long  and  closed  at  one  end.  This  end 
of  the  tube  may  be  heated  by  directing  the  blowpipe  flame  against 
it,  or  more  easily  by  holding  it  in  the  flame  of  the  alcohol  lamp  or 
Bunsen  gas  burner.  The  heat  is  applied  gently  at  first,  and  then 
more  strongly  if  the  reaction  seems  to  demand  it.  The  most  essen- 
tial feature  of  this  test  is  that  the  mineral  is  heated  nearly  out  of 
contact  with  the  air ;  and  the  principal  changes  or  reactions  observ- 
able are  (i)  fusion,  and  (2)  the  formation  of  a  sublimate  in  the 
upper  part  of  the  tube.  Few  minerals  are  melted ;  and  the  only 
minerals  yielding  sublimates  are  those  that  are  volatile  or  contain 
volatile  constituents,  such  as  sulphur,  arsenic,  mercury,  water,  etc. 

Heating  in  the  Open  Tube. — The  mineral,  preferably  in  the 
form  of  one  or  several  small  grains,  or  of  powder  if  it  decrepitates,  is 
placed  in  a  tube  of  hard  glass  three  inches  long  and  open  at  both  ends, 
the  best  position  being  three-fourths  of  an  inch  from  one  end ;  and 
this  point  is  then  heated  in  the  same  manner  as  the  bottom  of  the 
closed  tube,  the  tube  being  inclined  as  steeply  as  may  be  without 
having  the  mineral  slide  out.  A  current  of  air  is  thus  caused  to  pass 
over  the  mineral  while  it  is  ignited,  and  the  conditions  are  favorable 
for  oxidation.  The  most  important  reactions  are  (i)  the  character- 
istic odors  afforded  by  sulphides  and  arsenides,  and  (2)  the  subli- 
mates formed  in  the  upper  part  of  the  tube  and  consisting  chiefly 
of  the  oxides  of  the  same  substances  forming  sublimates  in  the  closed 
tube.  Sulphurous  and  other  acid  vapors  are  given  off  which  do  not 
condense  on  the  walls  of  the  tube  but  are  recognized  by  the  redden- 
ing of  a  slip  of  moistened  blue  litmus  paper  inserted  at  the  upper 
end  of  the  tube. 

Heating  on  Charcoal. — The  mineral,  in  about  the  same  quan- 
tity as  before,  is  placed  in  a  shallow,  saucer-shaped  cavity  excavated 
near  one  end  of  a  suitable  piece  of  charcoal.  The  charcoal  is  held 
so  that  the  flame  can  be  directed  upon  the  mineral  with  the  blow- 
pipe. If  the  mineral  decrepitates  or  flies  away,  it  may  be  finely 
pulverized  and  made  into  a  paste  with  water,  and  then  heated  grad- 
ually until  the  mass  coheres. 

The  principal  phenomena  to  be  observed  are:  (i)  The  odors  of 
burning  sulphur  and  arsenic,  the  latter  resembling  the  odor  of  garlic. 
These  are  afforded  by  the  elements  and  by  sulphides  and  arsenides. 
(2)  Fusion.  (3)  In  the  oxidizing  flame,  the  metals  are  oxidized  and 
characteristic  sublimates  or  coatings  of  the  oxides  are  formed  on  the 
charcoal,  which  may  be  recognized  by  their  color,  extent  and  degree 
of  volatility.  (4)  In  the  reducing  flame,  several  metals  are  readily 


reduced  to  the  metallic  state,  especially  if  carbonate  of  soda  is  added 
to  the  pulverized  minerals,  and  many  compounds  of  iron  will  become 
magnetic. 

Heating  in  the  Forceps. — If  possible,  a  minute,  slender  fragment 
or  splinter  should  be  held  by  its  larger  end  with  a  fine  point  pro- 
jecting well  beyond  the  end  of  the  forceps,  so  that  it  may  be 
introduced  into  the  tip  of  the  blue  or  oxidizing  flame  without  heating 
the  forceps.  If  the  mineral  decrepitates  so  that  it  can  not  be  held 
in  the  forceps,  it  may  be  finely  pulverized,  moistened  with  clean 
water,  and  supported  on  a  loop  of  platinum  wire. 

The  phenomena  to  be  observed  are  :  ( i )  The  degree  of  fusibility 
of  minerals.  If  the  fine  point  melts  into  a  round  globule,  it  is  readily 
fusible ;  if  it  is  only  slightly  rounded  on  the  end,  it  is  difficultly 
fusible,  and  so  on.  For  greater  precision,  the  behavior  of  the  mineral 
should  be  compared  with  that  of  similar  splinters  of  the  minerals 
forming  the  scale  of  fusibility.  (2)  The  colors  imparted  to  the 
flame  by  minerals.  These  are  often  very  characteristic,  and  form  a 
beautiful  and  delicate  test  for  the  following  elements  :  All  compounds 
of  soda  yield  a  bright  reddish  yellow  flame.  Potash,  in  most  of  its  com- 
pounds, tinges  the  flame  bluish  violet.  Lithia  gives  ^.purplish  red,  lime 
a  yellowish  red  and  strontia  a  pure  red^  color  to  the  flame.  Baryta, 
copper,  phosphoric  add  and  boric  acid  give  different  shades  of  green. 
But  the  chloride  of  copper  colors  the  flame  azure-blue.  (3)  The  colors 
imparted  to  the  minerals  themselves,  when  they  are  first  moistened  with 
a  solution  of  nitrate  of  cobalt  and  then  strongly  heated.  Alumina  com- 
pounds become  blue,  zinc  oxide  green  and  magnesia  compounds  flesh-red. 

Fusion  with  Borax  and  Salt  of  Phosphorus. — The  tests 
with  these  reagents  are  most  conveniently  made  on  a  short  piece  of 
platinum  wire,  one  end  of  which  is  bent  into  a  loop  one-tenth  of  an 
inch  in  diameter.  The  loop  is  heated  to  redness  and  dipped  into  the 
pulverized  flux ;  the  portion  which  adheres  to  the  wire  is  fused  in 
the  blowpipe  flame ;  and  this  process  is  repeated  until  a  full  round 
bead  of  the  flux  is  formed.  When  the  bead  is  complete,  and  while 
it  is  still  hot,  it  is  touched  to  the  pulverized  mineral,  so  that  a  small 
portion  of  the  latter  adheres.  The  bead  is  then  strongly  heated, 
usually  with  the  oxidizing  flame,  until  the  mineral,  if  soluble,  is  com- 
pletely dissolved  in  the  bead.  These  tests  are  especially  adapted  to  the 
detection  of  the  various  metallic  oxides  ;  and  the  chief  phenomenon  to 
be  observed  is  the  color  imparted  to  the  bead  or  glass  by  the  oxide. 

Alkaline  Reaction. — A  fragment  of  the  mineral  is  strongly  heated 
in  the  forceps  or  on  charcoal,  and  then  placed  upon  a  strip  of  red 
litmus  paper  and  moistened  with  a  drop  of  water.  If  the  color  of 
the  paper  is  changed  to  blue,  the  reaction  is  alkaline.  This  is  a 
valuable  test  for  the  alkalies  and  alkaline  earths. 


i8 

Dissolving  in  Acid. — Chlorhydric  (muriatic)  acid  answers  in  most 
cases,  nitric  and  sulphuric  acids  being  rarely  required.  The  acid  should 
be  used  full  strength,  except  when  dilute  acid  is  especially  called  for ; 
and  it  is  very  important,  especially  with  silicates,  that  the  mineral 
to  be  tested  should  be  in  the  form  of  an  impalpable  powder.  The 
behavior  of  minerals  with  acids  is  most  conveniently  observed  in  the 
test  tube.  A  small  quantity  of  the  pulverized  mineral  is  placed  in  the 
bottom  of  the  tube,  covered  with  one  or  two  inches  of  acid,  and 
heat  applied  gently  until  the  acid  boils. 

List  of  the  Principal  Constituents  of  Minerals,  with  the  Tests  em- 
ployed in  the  Tables  for  the  Detection  of  Each. — The  substances  are 
arranged  alphabetically,  for  convenience  of  reference  ;  and  the  student 
is  expected  to  turn  to  this  and  the  preceding  section  for  full  explan- 
ations of  the  tests  indicated  in  the  tables. 

Alumina  is  recognized,  in  fusible  minerals,  by  the  beautiful  blue 
color  which  they  assume  when  strongly  heated  and  then  moistened  with 
cobalt  solution  and  heated  again.  Hard  minerals  must  be  pulverized 

Antimony  and  most  of  its  compounds  fuse  and  yield  dense  white 
fumes  of  antimony  oxide  when  heated  on  charcoal.  The  oxide  par- 
tially condenses  on  the  coal,  forming  an  extended  white  coating,  which 
is  volatile  in  the  blowpipe  flame. 

Arsenic  and  nearly  all  of  its  compounds  yield  a  sublimate  of  me- 
tallic arsenic  in  the  closed  tube,  and  a  white  crystalline  sublimate  of 
arsenious  acid  in  the  open  tube.  On  charcoal,  this  element  is  re- 
cognized by  the  abundant  gray  smoke,  the  strong  garlic  odor,  and 
the  extremely  volatile  gray  coating  which  it  forms  on  the  coal. 

Baryta  is  recognized  by  the  yellowish  green  color  imparted  to  the 
blowpipe  flame  by  all  of  its  compounds  except  silicates. 

Bismuth  fuses,  volatilizes  and  oxidizes,  on  charcoal,  forming  a 
yellow,  volatile  coating. 

Boracic  Acid  colors  the  blowpipe  flame  an  intense  yellowish  green. 
This  test  is  more  reliable  if  the  mineral  is  moistened  with  sulphuric 
acid  before  heating. 

Carbonic  Acid  is  readily  set  free  in  the  gaseous  form,  from  all 
carbonates,  by  chlorhydric  acid,  especially  if  the  minerel  be  pulverized 
or  the  acid  heated.  The  effervescence  of  the  escaping  carbonic  acid 
is  distinguished  from  that  due  to  sulphuretted  hydrogen  by  the  offen- 
sive odor  of  the  latter  gas. 

Chlorine  is  most  conveniently  detected  by  adding  the  mineral  to  a 
salt  of  phosphorus  bead  which  has  been  saturated  with  copper  oxide, 
and  observing  the  intense  blue  color  which  is  imparted  to  the  blow- 
pipe flame. 

Chromium  is  recognized  by  the  emerald-green  color  which  its 
oxide  imparts  to  the  borax  bead. 


'9 

Copper  and  its  compounds  impart  a  green  color  to  the  flame  and 
to  the  borax  and  salt  of  phosphorus  beads.  In  most  cases  the  flame 
coloration  will  be  blue  if  the  mineral  be  first  moistened  with  chlorhy- 
dric  acid.  Copper  can  be  reduced  from  nearly  all  of  its  ores  by 
fusion  with  soda  on  charcoal. 

Fluorine  is  recognized  in  most  of  its  compounds  by  heating  the 
mineral  in  the  closed  tube  with  potassium  bisulphate  and  pulverized 
glass.  Fluorhydric  acid  is  set  free,  which  etches  the  glass  in  the 
bottom  of  the  tube,  and  a  white  sublimate  of  silicon  fluoride  is  formed 
in  the  upper  part  of  the  tube. 

Iron  may  be  recognized  by  the  yellow  and  brown  colors  which  its 
oxides  impart  to  the  borax  bead ;  and  by  the  fact  that  nearly  all  the 
compounds  of  iron  become  magnetic  when  heated,  especially  if  heated 
on  charcoal  with  soda. 

Lead  is  reduced  to  the  metallic  state  with  soda,  and  forms  a 
volatile  yellow  coating  of  lead  oxide  on  the  charcoal. 

Lime  colors  the  blowpipe  flame  yellowish  red ;  and  many  com- 
pounds of  lime  give  an  alkaline  reaction  after  heating. 

Lithia  usually  colors  the  flame  bright  purplish  red. 

Magnesia  is  recognized  in  many  of  its  compounds  by  the  pink 
color  which  they  assume  when  moistened  with  cobalt  solution  and 
strongly  heated. 

Manganese  is  recognized  in  all  of  its  compounds  by  the  highly 
characteristic  colors  which  it  imparts  to  the  fluxes.  •  With  borax  it  forms 
a  clear  bead  of  a  deep  amethystine  red  or  violet-red  color ;  while 
fusion  with  soda  (or,  if  necessary,  with  soda  and  nitre)  yields  an 
opaque,  bright  green  mass. 

Mercury  always  yields  a  sublimate  of  metallic  mercury  when  any 
of  its  compounds  are  heated  in  a  closed  tube  with  soda.  This  subli- 
mate consists  of  minute,  liquid  drops. 

Phosphoric  Acid  may  usually  be  recognized  by  the  green  color 
which  phosphates  impart  to  the  flame,  especially  if  previously  mois- 
tened with  sulphuric  acid.  Or  the  pulverized  mineral  may  be  fused 
in  the  closed  tube  with  a  bit  of  magnesium  wire,  and  a  drop  of  water 
added  to  the  fused  mass  when  cold,  evolving  phosphuretted  hydrogen, 
which  is  recognized  by  its  disagreeable  odor. 

Potassa  may  be  often  recognized  by  the  violet  color  which  it  im- 
parts to  the  flame. 

Silica  effervesces  with  soda  on  platinum  wire,  forming  a  clear  glass, 
if  the  soda  be  not  in  excess.  Most  of  the  silicates  are  decomposed 
by  salt  of  phosphorus,  leaving  a  cloudy  skeleton  of  silica  floating  in 
the  bead.  Many  hydrous  and  basic  silicates  are  decomposed  by 
chlorhydric  acid,  leaving  the  silica  in  the  form  of  a  stiff  jelly,  or  a 
floculent  powder. 


20 

Silver  is  easily  reduced  with  soda  on  charcoal,  and  forms  a  brown 
coating  of  silver  oxide. 

Soda  is  easily  recognized  by  the  intense  yellow  color  which  it  im- 
parts to  the  flame. 

Strontia  is  known  by  its  crimson  flame.  The  color  is  more  in- 
tense when  the  mineral  is  moistened  with  chlorhydric  acid. 

Sulphur,  as  it  occurs  in  sulphides,  may  be  recognized  in  many  ways. 
Bisulphides,  or  those  containing  the  largest  proportion  of  sulphur,, 
yield  sublimates  of  sulphur  in  the  closed  tube.  All  sulphides  redden 
moistened  blue  litmus  paper  in  the  open  tube.  If  any  sulphide  is 
fused  with  soda  in  the  closed  tube  and  the  fused  mass  transferred  to 
a  bright  silver  coin  and  moistened  with  water,  a  dark  brown  stain  of 
silver  sulphide  is  left  on  the  coin.  This  test  will  also  prove  the  pres- 
ence of  sulphur  in  any  sulphate,  if  a  little  pulverized  charcoal  is 
added  to  the  mixture  in  the  closed  tube  before  fusion,  or  the  fusion 
is  made  on  charcoal.  All  sulphides  effervesce  with  hot  chlorhydric 
acid,  evolving  sulphuretted  hydrogen,  which  is  recognized  by  its  odor. 

Tin  is  reduced  to  the  metallic  state  with  soda  on  charcoal. 

Water  may  be  expelled  from  nearly  all  hydrous  minerals  by  heat- 
ing in  the  closed  tube,  the  vapor  or  steam  condensing  in  the  upper 
part  of  the  tube  and  wetting  the  glass. 

Zinc  is  reduced  with  soda  on  charcoal,  but  the  metal  immediately 

oxidizes,  forming  a  coating  on  the  coal  which  is  yellow  when  hot  and 

white  when  cold.     The  white  and  gray  compounds  of  zinc  assume  a 

green  color  when  moistened  with  cobalt  solution  and  strongly  ignited. 

List  of  Apparatus  and  Reagents. 

Blowpipe.  The  simple  and  inexpensive  brass  blowpipe  used  by 
jewellers  answers  very  well  for  all  the  tests  described  in  these  tables ; 
although  the  chemical  blowpipe,  with  a  platinum  jet,  a  mouth -piece 
and  a  chamber  for  condensing  the  moisture  of  the  breath,  is,  of  course, 
rather  more  satisfactory  in  operation  and  more  durable. 

Fuel  and  Lamp.  The  most  satisfactory  source  of  heat  for  blow- 
pipe and  chemical  experiments  is  the  Bunsen  gas-burner;  the  aper- 
ture for  the  admission  of  air  at  the  bottom  of  the  burner  being  closed 
by  a  sliding  tube  when  the  blowpipe  is  used,  and  left  open  when  it 
is  desired  to  use  the  direct  heat  of  the  flame.  When  gas  is  not  avail- 
able, a  small  alcohol  lamp  is  recommended  as  most  generally  useful ; 
although  for  use  with  the  blowpipe  alone  a  common  oil  lamp  (olive 
oil  is  best)  or  stearine  candle  will  answer  in  most  cases.  The  blowpipe, 
enables  us  to  control  not  only  the  direction  but  the  quality  of  the 
flame.  The  reducing  flame  (R.  F.)  is  produced  by  holding  the  jet 
of  the  blowpipe  outside  of  the  flame  and  deflecting  the  entire  flame 
by  a  gentle  blast  without  essentially  changing  its  character.  The  re- 
ducing flame  should  be  used  whenever  it  is  desired  to  reduce  to  the 


21 

metallic  state,  or  partially  deoxidize,  metallic  oxides.  The  oxidizing 
flame  (O.  F.)  is  obtained  by  introducing  the  jet  into  the  flame  and 
blowing  more  strongly,  the  deflected  flame  forming  a  slender  blue 
cone.  This  is  the  flame  usually  employed,  especially  for  oxidizing  or 
roasting  minerals,  forming  coatings  on  charcoal,  and  whenever  a  high 
temperature  is  desired,  as  in  testing  the  fusibility  and  flame-coloration 
of  minerals. 

Forceps.  Common  steel  forceps  about  four  inches  long  will  answer 
in  most  cases ;  although  platinum-pointed  forceps  are  very  much 
better,  if  not  essential,  in  testing  fusibility  and  flame-coloration. 

Platinum  Wire.  A  piece  about  three  inches  long  of  moderately 
stout  wire  is  the  best.  Before  using,  a  circular  loop  one-tenth  of  an 
inch  in  diameter  should  be  formed  on  the  end  of  it. 

Glass  Tubes.  These  should  be  of  hard  glass,  one-eighth  to  one- 
fourth  inch  in  diameter,  and  three  to  four  inches  long.  The  open  tubes 
are  open  at  both  ends,  and  are  formed  by  simply  cutting  the  tubing 
with  a  file  into  pieces  of  the  proper  length.  The  closed  tubes  are 
closed  at  one  end,  and  are  formed  by  heating  pieces  seven  or  eight 
inches  long  in  the  middle  until  the  glass  is  soft  enough  to  be  drawn  apart. 

Charcoal.  This  important  support  should  be  made  from  soft  wood 
and  thoroughly  burned,  so  as  not  to  crack  or  snap  when  heated. 
Rectangular  pieces  four  to  eight  inches  long  and  two  inches  wide  are 
the  most  convenient. 

Agate  Mortar.  This  instrument  is  very  useful  in  reducing  min- 
erals to  a  fine  powder,  especially  for  treatment  with  acid ;  but  it  is 
unfortunately  somewhat  expensive. 

'  Hammer,  Anvil  and  Ring.  These  are  employed  to  break  and 
pulverize  fragments  of  minerals,  and  answer  in  most  cases  as  a  sub- 
stitute for  the  agate  mortar. 

File.  A  small  three-cornered  file  is  useful  for  testing  the  hardness 
and  streak  of  minerals,  and  for  cutting  glass  tubing.  A  notch  is 
made  with  the  file  in  one  side  of  the  tube,  which  is  then  gently  bent 
and  pulled  apart,  the  nails  of  the  two  thumbs  being  brought  together 
opposite  the  notch. 

Magnet.  A  small  magnet  aids  in  the  recognition  of  magnetic  minerals. 

Lens.     A  pocket  lens  or  magnifying  glass  is  useful  in  many  ways. 

Test-tubes  Small  test-tubes  of  hard  glass  are  needed  for  treat- 
ing minerals  with  acids. 

Soda.     (Carbonate  of  Sodium).     Borax   (Biborate    of    Spdium). 

Salt  of  Phosphorus   (Phosphate  of  Sodium  and  Ammonium). 

Oxide  of  Copper.     Cobalt  Solution  (Nitrate  of  Cobalt). 

Chlorhydric,  Sulphuric  and  Nitric  Acids. 

Litmus  Paper.  The  blue  paper  may  be  reddened  by  moistening 
it  and  holding  it  over  the  open  mouth  of  the  acid  bottle. 


SYNOPSIS    OF   THE    CLASSIFICATION    OF  MINERALS. 

SUBKINGDOM    OF    ELEMENTS. 

Class  of  Metals. 

1.  Gold  Group. — Gold,  silver. 

2.  Iron   Group. — Copper,  iron,  mercury. 
Class  of  Metalloids. 

3.  Arsenic  Grmtp. — Bismuth,  antimony,  arsenic. 

4.  Sulphur  Group. — Sulphur. 

5.  Carbon-Silicon   Group. — Diamond,    graphite. 

SUBKINGDOM  OF  BINARY  COMPOUNDS. 
Class  of  Sulphides,  Sulpharsenides,  Arsenides,  etc. 

GOLD,    IRON  AND   TIN   SUBCLASS. 

Pro  to  or  Galena,   Group 

6.  Galena  Family. — Galenite,  bornite,  argentite. 

7.  Blende  Family. — Sphalerite. 

8.  Pyrrhotite  Family. — Cinnabar,  millerite,  pyrrhotite, 

9.  Chalcocite  Family. — Chalcocite.  [niccolite. 
Deuto  or  Pyrite  Group. 

10.  Pyrite  Family. — Pyrite,  chalcopyrite,  smaltite,  cobaltite. 

11.  Marcasite  Family. — Marcasite,  arsenopyrite. 

ARSENIC^  AND   SULPHUR   SUBCLASS. 

12.  Realgar  Family. — Realgar. 

13.  Orpiment  Family. — Orpiment,  stibnite. 

14.  Molybdenite  Family. — Molybdenite. 

SULPHARSENITES,    SULPHANTIMONITES,    ETC. 

15.  Stephanite,  tetrahedrite,  pyrargyrite,  proustite. 
Class  of  Chlorides,  Bromides  and  Iodides. 

GOLD,    IRON   AND    TIN   SUBCLASS. 

Anhydrous  Division. 

1 6.  Halite  Family. — Halite,  cerargyrite. 
Oxychloride    Division. 

17.  Atacamite  Family. — Atacamite. 
Class  of  Fluorides. 

GOLD,    IRON    AND    TIN     SUBCLASS. 

Anhydrous    Division. 

1 8.  Fluorite  Family. — Fluorite. 

19.  Cryolite  Family. — Cryolite. 
Class  of  Oxides. 

GOLD,    IRON    AND    TIN    SUBCLASS. 

Anhydrous  Division. 
Protoxide   Group. 

20.  Cuprite  Family. — Cuprite. 

21.  Zincite  Family.- — Water,  zincite. 

22.  Melaconite  Family. — Melaconite. 
Protoxide  and  Sesquioxide  Group. 

23.  Spinel  Family. — Spinel,  magnetite,  franklinite,  chromite. 

24.  Chrysoberyl  Family. — Chrysoberyl. 


23 
Sesquioxide  Group. 

25.  Corundum  Family. — Hematite,  menaccanite,  corundum, 
Deutoxide    Group.  [perofskite. 

26.  Rutile  Family. — Cassiterite,  rutile,  zircon. 

27.  Brookite  Family. — Brookite,  pyrolusite. 
Hydrous  Division. 

28.  Turgiie  Family.- — Turgite. 

29.  Diaspore  Family. — Diaspore,  gothite,  manganite. 

30.  Limonite   Family. — Limonite. 

31.  Brucite  Family.     Brucite,  gibbsite. 

32.  Psilomelane  Family. — Psilomelane,  wad. 

CARBON-SILICON   SUBCLASS. 

33.  Anhydrous  Division.— ^Quaxtz. 

34.  Hydrous  Division. — Opal. 

SUBKINGDOM    OF   TERNARY    COMPOUNDS. 

Class  of  Tantalates  and  Columbates. 

35.  Tantalite  Family. — Tantalite,  columbite,  samarskite. 
Class  of  Phosphates,  Arsenates,  etc. 

Anhydrous  Division. 

36.  Apatite  Family. — Apatite,  pyromorphite.  mimetite, 
Hydrous  Division.  [vanadinite. 

37.  Vivian ite  Family. — Vivianite,  erythrite. 

38.  Wave  Hi te  Family. — Lazulite,  wavellite,  turquois,  autunite. 
Class  of  Borates. 

39.  Sassfllite  Family. — Sassolite. 

40.  Borax  Family. — Borax,  ulexite. 

Class  of  Tungstates,  Molybdates  and  Chromates. 

41.  Wolframite  Family. — Wolframite,  wulfenite,  scheelite. 
Class  of  Sulphates. 

Anhydrous  Division . 

42.  Celestite  Family. — Barite,  celestite,  anhydrite,  anglesite. 
Hydrous  Division. 

43.  Gypsum  Family. — Gypsum. 
Class  of  Carbonates. 

Anhydrous  Division. 

44.  Calcite  Family. — Calcite,  dolomite,  magnesite,  siderite, 

rhodochrosite,  smithsonite. 

45.  Aragonite    Family. — Aragonite,    witherite,    strontianite, 
Hydrous  Division.  [cerussite. 

46.  Malachite  Family. — Malachite,  azurite. 
Class  of  Silicates. 

Anhydrous  Division. 
Bisilicate  Group. 

47.  Pyroxene  Family. — Enstatite,  hypersthene,  wollastonite, 

"pyroxene. 

48.  Spodumene  Family. — Spodumene,  rhodonite. 

49.  Amphibole  Family. — Amphibole. 

50.  Beryl  Family. — Beryl. 
Unisilicate   Group. 

5'i.     Phenacite  Family. — Willemite. 

52.  Chrysolite  Family. — Chrysolite. 

53.  Garnet  Family. — Garnet. 

54.  Vesuvianite  Family. — Vesuvianite. 

55.  Epidote  Family. — Epidote,  allanite,  zoisite. 


24 

56.  Mica  Family. — Muscovite,  biotite,  phlogopite,  lepidom- 

elane,  lepidolite. 

57.  Leucite  Family. — Sodalite,  leucite,  lapis-lazuli. 

58.  Scapolite  Family. — Wernerite. 

59.  Nephelite  Family. — Nephelite,  cancrinite. 

60.  Feldspar  Family. — Orthoclase,    albite,  oligoclase,  labrad- 

.     orite,  anorthite. 
Sub  silicate  Group. 

61.  Chondrodite  Family. — Chondrodite. 

62.  Tourmaline  Family. — Tourmaline. 

63.  Andalusite  Family. — Andalusite,  fibrolite,  cyanite. 

64.  Euclase  Family. — Datolite,    topaz. 

65.  Titanite  Family. — Titanite. 

66.  Staurolite  Family. — Staurolite. 
Hydrous  Division. 

General  Subdivision. 

67.  Pec  to  lite  Family. — Pectolite,  laumontite. 

68.  Chrysocolla  Family. — Chrysocolla. 

69.  Calamine  Family. — Calamine,  prehnite.' 
70..     Apophyllite  Family. — Apophyilite. 

Zeolite  Subdivisio  n . 

71.  Mesotype  Family. — Thomsonite,  natrolite. 

72.  Analcite  Family. — Analcite. 

73.  Chabazite  Family. — Chabazite,  gmelinite. 

74.  Stilbite  Family. — Stilbite,  heulandite. 
Ma  rga  rophyllite  Sub  division. 

75.  Talc  Family. — Talc,  pyrophyllite. 

76.  Sepiolite  Family. — Sepiolite,  glauconite. 

77.  Serpentine  Family. — Serpentine,  deweylite. 

78.  Kaolinite  Family. — Kaolinite. 

79.  Finite  Family. — Finite. 

80.  Hydromica  Family. — Hydromica. 

81.  Chlorite  Family.— Ripidolite,  prochlorite. 

82.  Chloritoid  Family. — Margarite,  chloritoid. 
Hydrocarbons. 

83.  Simple  Hydrocarbons. — Petroleum,  etc. 

84.  Oxygenated  Hydrocarbons. — Amber,    copal,  coal,  etc. 


To  aid  students    in  referring  new    minerals    to  their  proper  places 

in  the  classification,  and    thus    determining   their  relations    to    other 

minerals,  the  name  of  each  species  in   the  tables  is  accompanied   by 
the  number  of  the  family  to  which  it  belongs. 


GENERAL   CLASSIFICATION. 


A.     METALLIC  LUSTRE. 

B. 

I. 

Color  red  or  brown. 

Page. 

I.     Str< 

i.     Very  soft 

26 

i. 

2;       Soft    .... 

26 

2. 

3.     Hard     .... 

28 

3- 

4.     Very  hard 

.       28 

4- 

II. 

Color  yellow. 

II.  Str 

i.     Very  soft 

30 

i. 

2.        Soft    .... 

•       30 

2. 

3.     Hard      .... 

30 

3- 

4.     Very  hard  . 

32 

4- 

Ill 

.     Color  black. 

III.     81 

i.     Very  soft 

32 

T- 

2.       Soft       .... 

34 

2. 

3.     Hard       . 

36 

3- 

4.     Very  hard    . 

38 

4- 

IV 

.     Color  gray. 

IV.     S 

i.     Very  soft 

40 

i. 

2.       Soft       .... 

40 

2. 

3.     Hard       . 

42 

3- 

4.     Very  hard  . 

44 

4- 

V. 

Color  white. 

V.     Sti 

i.     Very  soft 

46 

i. 

2.     Soft 

.46 

2. 

3.     Hard      .... 

46 

3- 

4.     Very  hard  . 

.46 

4- 

5- 

B.     NON-METALLIC  LUSTRE,. 

Streak  red  or  brown. 

Very  soft 
Soft 

Hard       . 
Very  hard  . 

*ak  yellow. 
Very     soft 
Soft 

Hard      .... 
Very  hard  . 
Streak  black. 
Very  soft 

Soft     .... 
Hard       .... 
Very  hard  . 

Streak  green  or  blue. 

Very  soft 

Soft     .... 
Hard'      .... 
Very  hard  . 

Streak  white  or  gray. 
Very  soft 

Soft     .... 
Hard        . 
Very  hard  . 
Adamantine 


OP  THB   '"$5 
'rr-vTYTTWWCTiTiT! 


26 


A.     MINERALS     WITH 


Analytical  Key. 


Species.  Composition.        Lustre. 


Color.  Streak. 


Foli^ekstic 

Phlogopite(56). 

(KMgAl)2     Pearly  to 
SiO4.    submetallic. 

Yellow   to      ^ 
brown.:Gra>r- 

i 

Brown  Coal 

C,  H,  O,  etc. 

Resinous  to 
dull. 

Brown  to      -^ 
black.|Brown- 

1 

Realgar  (12). 

AsS. 

Resinous. 

Aurora-red. 

Aurora-red. 

^ 

G.  3-6. 

Proustite  (15). 

Ag8AsS3. 

Adamantine 
to  dull. 

Cochineal- 
red. 

Cochineal- 
red. 

Pyrargyrite(i5). 

Ag?SbS3. 

Adamantine 
to  dull. 

Black  to 
,.       ,       Cocmneal- 
cocmneal-                          , 
i                    reel. 
red. 

G.  9, 
when  pure. 

Cinnabar  (8). 
Compare  Red  Ochre 

HgS. 

Adamantine 
to  dull. 

Cochineal- 
red. 

Scarlet. 

4 

Micaceous. 
Folise  elastic. 

Phlogopite  (56). 

(KMgAl)2 
Si04. 

Pearly  to 
submetallic. 

Yellow  to 
brown. 

Gray. 

5 

"« 

* 

Streak  red. 
Malleable. 

Copper    (2). 

Cu. 

Metallic. 

Copper-red. 

Copper-red. 

^0 

6 

Streak 

* 

bright  red. 
G.  9,  when 

Cinnabar  (8). 

HgS. 

Adamantine 
to    dull. 

Cochineal- 
red. 

Scarlet. 

pure. 

Proustite  (15). 

Ag3AsS3. 

Adamantine 
to    dull. 

Cochineal- 
red. 

Cochineal- 
red. 

Streak 

I 

bright  red. 

Pyrargyrite(i5). 

Ag3SbS3. 

Adamantine 
to  tiull. 

Black   to 
cochineal- 
red. 

Cochineal- 
red. 

^ 

G.     5-6. 

Cuprite   (20). 

Cu2O. 

Adamantine 
to    dull. 

Red  to 
brown. 

Red. 

Streak 
bright 
orange. 

Zincite   (21). 

ZnO. 

Sub- 
adamantine. 

Red  to 
orange. 

Orange. 

Streak  dull 

Turgite  (28). 

2Fe2O3+ 
H2O. 

Submetallic 
to  silky. 

Reddish 
black  to  red. 

Red. 

red  to 

brown. 

C-.  3-4- 

Sphalerite  (7). 

ZnS. 

• 
Resinous. 

Brown. 

Brown  to 
yellow. 

, 

Compare  Hematite. 

METALLIC    LUSTRE. 


27 


H. 

Tenacity. 

G. 

Form. 

Cleavage. 

Other 

Properties. 

Confirmatory  Chemical  Tests. 

2-75 
I. 
2. 

Elastic  and 
sectile. 

2.8 

1.25 

3-5 

IV.  Foliated. 

Basal, 

perfect. 

Transparent 
to  opaque. 

Infusible;  decomposed  by  strong 
sulphuric  acid. 

Brittle   to 
sectile. 

Compact    or 
laminated. 

None. 

Opaque. 

Readily  ignited,  burning  with  flame. 

Brittle. 

V.     Also 
massive. 

Clinopina- 
coidal  and 
basal. 

Transparent 
to 
translucent. 

Volatile  and  combustible,  burning 
with  a  blue  flame  and  arsenical 
odor. 

2. 

Brittle. 

5-5 

III.     Also 
massive. 

Conchoidal. 

Translucent. 

Gives  reactions  for  arsenic  and  silver. 

2. 

Brittle. 

5.8 

III.     Also 
massive. 

Conchoidal. 

Translucent. 

Gives  reactions  for  antimony  and 
silver. 

2. 

Brittle  to 
sectile. 

9- 

III.    Usually 
massive. 

Uneven. 

Usually 
opaque. 

Volatile;  with  soda  in  closed  tube 
yields  sublimate  of  mercury. 

2-75 

Elastic  and 
sectile. 

2.8 

IV.  Foliated. 

Basal, 
perfect. 

Transparent 
to  opaque. 

Infusible;  decomposed  by  strong 
sulphuric  acid. 

2-75 

Malleable. 

8.8 

I.  Also  mas- 
sive and 
arborescent. 

None. 

Opaque. 

Fuses  readily;  green  solution  with 
nitric  acid,  which  becomes  blue 
with  ammonia. 

2-5 
2-5 

Brittle  to 

sectile. 

9- 

III.    Usually 
massive. 

Uneven. 

Usually 
opaque. 

Volatile;  with  soda  in  closed  tube 
yields  sublimate  of  mercury. 

Brittle. 

5-5 

III.     Also 
massive. 

Conchoidal. 

Translucent 
to  opaque. 

Gives  reactions  for  arsenic  and  silver. 

2-5 

Brittle. 

5.8 

III.     Also 
massive. 

Conchoidal. 

Translucent 
to  opaque. 

Gives  reactions  for  antimony  and 
silver 

3-5 

4- 

Brittle. 

6. 

I.  Also  cap- 
illary  and 
massive. 

Octahedral. 

Translucent 
to  opaque. 

Colors  flame  green  and  fuses  readily, 
yielding  metallic  copper. 

Brittle. 

5-5 

III.     Also 
massive. 

Basal, 

perfect. 

Usually 
opaque. 

Infusible;  soluble  in  acids;  zinc 
coating  with  soda  on  charcoal. 

5- 

Brittle. 

3-7 

Massive, 
botryoidal, 
fibrous,  etc. 

Uneven, 
splintery, 
etc. 

Opaque. 

Yields  water  in  closed  tube;  mag- 
netic on  charcoal. 

3-5 

Brittle. 

4- 

I.     Also 
massive. 

Dodecahe- 
dral,  perfect. 

Transparent 
to  opaque. 

Reactions  for  sulphur;  zinc  coating 
with  soda  on  charcoal;  effervesces 
in  acid  (H2S). 

28 


A.     MINERALS  WITH 


Analytical    Key. 

Species. 

Composition. 

Lustre. 

Color. 

Streak. 

1.1 

«*£  § 

Streak 

Pyrrhotite  (8). 

Fe7S8. 

Metallic. 

Bronze-yel- 
iow  to    cop- 
per-red. 

Dark  gray- 
ish black. 

Jl 

grayish 
black. 

Bornite   (6). 

(FeCu)S. 

Metallic. 

Dark  cop- 
per-red. 

Pale  grayish 
black. 

Niccolite   (8). 

NiAs. 

Metallic. 

Pale  cop- 
per-red. 

Brownish 
black. 

Streak 

black. 

Pyrrhotite    (8). 

Fe7S8. 

Metallic. 

Bronze-yel- 
low to    cop- 
per-red. 

Grayish 
black. 

Sphalerite  (7). 

ZnS. 

Resinous. 

Brown. 

Brown. 

Streak  gray 

. 

to  brown. 

1 

Brookite  (27). 

Ti02. 

Adamantine. 

Brown. 

Pale  brown. 

8 

Compare    Cuprite. 

1 

•2 

Zincite  (21). 

ZnO. 

Sub- 
adamantine. 

Red  to 
orange. 

Orange. 

1 

d) 

ns 

si 

Streak 
yellow  or 
orange. 

Gothite  (29). 

Fe203 
+H20. 

Adamantine 
to  dull. 

Brown. 

Yellow. 

1 

Limonite  (30). 

2Fe2O3 
+3H20. 

Submetallic 
to  silky. 

Brown. 

Yellow. 

N" 

Cuprite  (20). 

Cu2O. 

Adamantine 
to  dull. 

Red  to 
brown. 

Red. 

Streak  red. 

Turgite  (28). 

2Fe2O3 
+H20. 

Submetallic 
to  silky. 

Reddish 
black 
to  red. 

Red. 

Hematite   (25). 

Fe203. 

Metallic 
to  dull. 

Black  to  red. 

Red. 

G.  nearly  7. 

Cassiterite  (26). 

SnO2. 

Adamantine. 

Brown. 

Gray  to 
brown. 

'B 

! 

1 

Rutile  (26). 

TiO2. 

• 

Adamantine.  Brown. 

1 

Gray  to 
yellowish. 

t& 

G.  4.2 

Brookite  (27). 

Ti02. 

Adamantine. 

Brown. 

Pale  brown. 

iMETALLIC     LUSTRE. 


29 


H. 

Tenacity. 

G. 

Form. 

Cleavage. 

Other 
Properties. 

Confirmatory  Chemical  Tests. 

3-5 

Brittle. 

4-5 

III.  Usually 
massive. 

Uneven. 

Opaque. 
Tarnishes. 

Fusible  to  a  black,  magnetic  mass; 
usually  slightly  magnetic    before 

fusion. 

Opaque 

3- 

Brittle. 

5- 

I.  Usually 
massive. 

Octahedral, 
in  traces. 

Blue  and 
green 

Gives  reactions  for  copper;   fuses 
to  a  black,  magnetic  globule. 

tarnish.' 

5-25 

Brittle. 

7-5 

III.  Usually 
massive. 

Uneven. 

Opaque. 

Arsenic    fumes     and    coating    and 
magnetic  globule  on  charcoal. 

4-5 

Brittle. 

4-5 

III.  Usually 

Uneven. 

Opaque. 

:  Fusible  to  a  black,  magnetic  mass; 
usually    slightly  magnetic    before 

fusion. 

4- 

Brittle. 

4- 

I.  Usually 
massive. 

Dodecahe- 
dral,  perfect. 

Transparent 
to  opaque. 

Reactions  for  sulphur;  zinc  coating 
with  soda  on  charcoal;  effervesces 
in  acid    (H2S). 

5-5 

Brittle. 

4.2 

IV.  Small 
square 
crystals. 

Prismatic, 
indistinct. 

Translucent 
to  opaque. 

Infusible  and  insoluble. 
\ 

III.  Also 

Basal, 

Usually 

Infusible;  soluble  in  acid;  zinc  coat- 

4-5 

Brittle. 

5-5 

massive. 

perfect. 

opaque. 

ing  with  soda  on  charcoal. 

IV.  Usually 

5-25 

Brittle. 

4.2 

massive,  ti- 
brous  or 

Prismatic, 
perfect. 

Opaque. 

Water  in  closed  tube;  magnetic  on 
charcoal. 

botryoidal. 

Massive, 

Uneven, 

5-25 

Brittle. 

4- 

botryoidal, 

splintery, 

Opaque. 

Like    gothite. 

fibrous,  etc. 

etc. 

V 

4- 

Brittle. 

6. 

I.  Also 
capillary  and 
massive. 

Octahedral. 

Translucent 
to  opaque. 

Colors  flame  green  and  fuses  read- 
ily, yielding  metallic  copper. 

5-5 

Brittle. 

3-7 

Massive, 
botryoidal, 
fibrous,  etc. 

Uneven, 
splintery, 
etc. 

Opaque. 

Water  in  closed  tube;  magnetic  on 
charcoal. 

Massive, 

Uneven, 

5-5 

Brittle. 

4-5 

botryoidal, 
fibrous,  etc. 

splintery, 
etc. 

Opaque. 

No  water  in  closed  tube;  magnetic 
on  charcoal. 

6.5 

Brittle.' 

6.8 

II.  Also 
massive,  bot- 
ryoidal, etc. 

Prismatic, 
indistinct. 

Vearly 
opaque. 

Infusible  and  insoluble;  with  soda 
on  charcoal  reduced  to  metallic  tin. 

6.25 

Brittle. 

4.2 

II.  Also 
massive. 

Prismatic, 
distinct. 

Nearly 
opaque. 

[nfusible  and  insoluble. 

6. 

Brittle. 

4.2 

IV.  Small 
square 
crystals. 

Prismatic, 
indistinct. 

Translucent 
to  opaque. 

Like  rutile. 

A.     MINERALS  WITH 


Analytical    Key. 

Species. 

Composition. 

Lustre. 

Color. 

Streak. 

I 

Malleable. 

Gold  (i). 

Au. 

Metallic. 

Gold- 
yellow. 

Yellow. 

Micaceous. 
Foliae  elastic. 

Phlogopite  (56). 

(KMgAl)2 
SiO4. 

Pearly  to 

submetallic. 

Yellow  to 
brown. 

Gray. 

Brittle. 

Orpiment  (13). 

A,s, 

Pearly  to 
resinous. 

Lemon- 
yellow. 

Yellow. 

Streak 
yellow. 
Malleable. 

Gold  (i). 

Au. 

Metallic. 

yellow. 

Yellow. 

Sphalerite  (7). 

ZnS. 

Resinous. 

Brown  to 
yellow. 

Dull  yellow. 

Streak 
yellow. 
Brittle. 

Millerite   (8). 

NiS. 

Metallic.  , 

Brass- 
yellow. 

Bright 
yellow. 

olor  Yellow. 

1 

Zincite   (jzi). 

ZnO. 

Sub- 
adamantine. 

Red  to 
orange. 

Orange. 

Chalcopyrite 

(10). 

(CuFe)S2. 

Metallic. 

Brass- 
yellow. 

Greenish 
black. 

0 

fcj 

Streak 
black  or 

Pyrrhotite  (8). 

Fe7S8. 

Metallic. 

Bronze- 
yellow 

Grayish 
black. 

nearly  so. 

Bornite  (6). 

(CuFe)S. 

Metallic. 

Brownish 
copper-red 

Gravish 

black. 

Streak 
nearly 
black. 

Chalcopyrite 

(10). 

(CuFe)S2. 

Metallic. 

Brass- 
yellow 

Greenish 
black. 

1 

H.  about  4. 

Pyrrhotite   (8). 

Fe7S8. 

Metallic. 

Bronze- 
yellow 

Grayish 
black. 

Marcasite  (n). 

FeS2. 

Metallic. 

Grayish 
yellow. 

Grayish 
black. 

Streak 
nearly 
black 

Pyrite  (10). 

FeS2. 

Metallic. 

Pale  brass- 
yellow. 

Greenish 
black. 

H.  about   6 

Arsenopyrite 

00 

FeAsS. 

Metallic. 

White  to 
gray 

Dark  gray- 
ish  black. 

METALLIC  LUSTRE. 


H. 

2-5 

Tenacity. 

G. 

Form. 

Cleavage. 

Other 
Properties. 

Confirmatory  Chemical   Tests. 

Malleable. 

19-3 

I.  Usually 
in  grains 
or  nuggets. 

None. 

Opaque. 

Readily  fusible;  insoluble  in  com- 
mon acids;  does  not  tarnish. 

2-75 

Elastic  and 
sectile. 

2.8 

3-5 

IV.  Foliated. 

Basal, 
perfect 

Transparent 
to  opaque 

Infusible;  decomposed  by  strong 
sulphuric  acid. 

i-75 

Sectile  to 
brittle. 

IV.  Foliated 
and  massive. 

Macropina- 
coidal,  very 
perfect. 

Translucent. 

Volatilizes  and  gives  reactions  for 
arsenic  and  sulphur. 

3- 

Malleable. 

19-3 

I.  Usually 
in  grains 
or  nuggets. 

None.  - 

Opaque. 

Readily  fusible;  insoluble  in  com- 
mon acids;  does  not  tarnish. 

3-5 

Brittle. 

4- 

I.  Usually 
massive. 

Dodecahe- 
dral,  perfect. 

Translucent 
to  opaque 

Reactions  for  sulphur;  with  soda 
on  charcoal  gives  a  zinc  coating. 

3-25 

Brittle. 

5- 

III.  Acicular 
or  fibrous. 

Rhombohe- 
dral. 

Opaque. 

Reactions  for  sulphur;  fuses  on 
charcoal  to  a  magnetic  globule. 

4- 
3-5 

Brittle. 

5-5 

III.  Also 
massive. 

Basal, 
perfect. 

Usually 
opaque 

Infusible;  soluble  in  acids;  zinc 
coating  with  soda  on  charcoal. 

Brittle. 

4-2 

II.  Usually 
massive. 

Uneven. 

Opaque. 
Iridescent 
tarnish 

Sulphur  in  closed  tube;  magnetic 
globule  on  charcoal;  green  solu- 
tion in  nitric  acid. 

3-5 

Brittle. 

4-5  ' 

III.  Usually 
massive. 

Uneven. 

Opaque. 

Fusible  to  magnetic  mass;  usually 
slightly  magnetic  before  fusion. 

3- 

4- 

Brittle. 

5- 

I.  Usually 
massive. 

Uneven. 

Opaque. 
Blue  and 
green  tar- 
nish 

Reactions  for  copper;  fuses  to 
magnetic  globule. 

Brittle. 

4-2 

II.  Usually 
massive. 

Uneven. 

Opaque. 
Iridescent 
tarnish. 

Sulphur  in  closed  tube;  magnetic 
globule  on  charcoal;  green  solu- 
tion in  nitric  acid. 

4-5 
6. 

Brittle. 

4-5 

III.  Usually 
massive. 

Uneven. 

Opaque. 
Tarnishes. 

Fusible  to  magnetic  mass;  usually 
slightly  magnetic  before  fusion. 

Brittle. 

4-7 

IV.  Often 
massive  or 
globular. 

Prismatic. 

Opaque. 
Decomposes 
readily. 

Sufphur  in  closed  tube;  magnetic 
residue  on  charcoal. 

I.  Cubes  and 

6. 

Brittle. 

5- 

pyritohe- 
drons;   often 

Uneven. 

Opaque. 

Like  marcasite. 

massive. 

5-5 

Brittle. 

6.2 

IV.  Also 
massive. 

Prismatic, 
distinct. 

Opaque. 
Tarnishes. 

Arsenic  coating  and  magnetic  resi- 
due on  charcoal;  arsenic  sublimate 
in    tube. 

A.     MINERALS    WITH 


Analytical  Key. 

Species. 

Composition. 

Lustre. 

Color. 

Streak. 

Streak 

Sphalerite  (7). 

ZnS. 

Resinous. 

Dull  yellow. 
yellow.1 

r^j 

yellow. 

i 

Crystalline 

i 

5 

or  granular. 

Zincite  (21}. 

ZnO. 

Sub- 
adamantine. 

Red  oran  re  OranSe- 

•« 

6 

2 

1 
1 

a 

Streak 

Limonite   (30). 

2Fe203-r- 
3H20. 

Submetallic 
to  silky. 

Brown  to 
yellow. 

Yellow. 

o 

yellow. 

Clj 

Compact  or 

s 

2 

hbrous. 

Gothite   (zg). 

Fe203+ 
H20. 

Imperfect 
adamantine. 

^"yenow.™™- 

o 

Marcasite  (11). 

FeS2. 

Metallic. 

Grayish           Grayish 
yellow.              black. 

kj 

"E 

Grayish 

H 

1 

yellow. 

Dark 

to 

Arsenopyrite 

FeAsS. 

Metallic. 

Whlte  wav     srayish 

£ 

/               (")• 

black. 

f 

Pale  brass- 
yellow. 

Pyrite   (10). 

FeS2. 

Metallic. 

Pale  brass-    Greenish 
yellow.              black. 

Micaceous. 
Foliae 
elastic. 

Biotite   (56). 

(AlMgK 

Fe)a  Si04. 

Pearly  to 
subinetallic. 

Black. 

Gray. 

Iron-black 

Graphite  (5). 

C. 

Metallic. 

to 

Black. 

Greasy    feel. 

dark  gray. 

Usually 

foliated. 

Molybdenite 

MoS2. 

Metallic. 

Lead-gray.     Lead-gray. 

1 

i 

Malleable 
and  sectile. 

Argentite   (6). 

AgS. 

Metallic. 

Blackish         Blackish 
lead-gray.       lead-gray. 

H 

«8 

o 

« 

? 

0 

u 

Wad  (32). 

H2O. 

Dull. 

Black.             Black. 

" 

Streak 
black. 

Pyrolusite  (27). 

MnO2. 

Metallic. 

Iron-black 
to 

Black. 

dark  gray. 

Stephanite  (15). 

Ag5SbS3. 

Metallic. 

Iron-black. 

Iron-black. 

Streak  red. 

Pyrargyrite(is). 

Ag3SbS3. 

Adamantine. 

Black  to        j  cochineal- 
cochineal-;                 red 
red. 

METALLIC    LUSTRE. 


33 


H.        Tenacity.         G.           Form. 

Cleavage. 

Other 

Properties. 

Confirmatory  Chemical  Tests. 

4- 

Brittle. 

4- 

I.  Usually 
massive 

Dodecahe- 
dral,  perfect 

Translucent 
to  opaque 

Reactions  for  sulphur;   zinc  coating 
with  soda  on  charcoal;  effervesces 
in  acid  (H2S). 

4-5 

Brittle. 

5-5 

III.  Also 
massive 

Basal, 
perfect 

Usually 
opaque 

Infusible;     soluble  in    acids;     zinc 
coating  with  soda  on  charcoal. 

5-25 

Brittle. 

4- 

Massive, 
botryoidal, 
fibrous,  etc. 

Uneven, 
splintery, 
etc. 

Opaque. 

Water  in  closed  tube;    magnetic 
residue  on  charcoal. 

5-25 

Brittle. 

4.2 

IV.  Massive, 
fibrous  or 
botryoidal. 

Prismatic, 
perfect. 

Opaque. 

Like  limonite. 

6.5 

Brittle. 

4-7 

IV.  Often 
massive  or 
globular. 

Prismatic. 

Opaque. 
Decomposes 
readily. 

Sulphur  in  closed    tube;     magnetic 
residue  on  charcoal. 

6. 

Brittle. 

6.2 

IV.  Also 
massive. 

Prismatic, 
distinct. 

Opaque. 
Tarnishes. 

Arsenic  coating  and  magnetic 
residue  on  charcoal;  arsenic  sub- 
limate in  tube. 

I.  Cubes, 

6.5 

Brittle. 

etc.  ;   also 
massive. 

Uneven. 

Opaque. 

Sulphur  in    closed  tube;     magnetic 
residue  on  charcoal. 

2-5 

Elastic  and 
sectile. 

2.9 

III.  Foliated. 

Basal, 
perfect. 

Transparent. 
Green  by 
transmitted 

infusible;     decomposed    by   strong 
sulphuric  acid. 

light. 

1.25 

Sectile. 

2.2 

III.  Usually 
foliated. 

Basal, 
perfect. 

Opaque. 
Greasy  feel. 

Infusible;    unaltered  by  acids. 

1.25 

Sectile. 

4.6 

III.  Usually 
foliated. 

Basal, 
perfect. 

Opaque. 
Greasy  feel. 

Infusible;   reactions  for  sulphur. 

2. 

Malleable 
and  sectile. 

7-3 

I.  Also 
massive. 

Uneven. 

Opaque. 

Reactions  for    sulphur;     silver    on 
charcoal. 

Water  in  closed  tube;   amethvstine 

I. 

Earthy. 

3-8 

Amorphous. 

Earthy. 

Opaque. 

bead  with  borax;  evolves  chlorine 

with  HC1. 

Brjttle. 

4.8 

IV.  Usually 
columnar  or 

Prismatic. 

Opaque. 

Infusible;   amethystine    bead     with 
borax;  evolves  chlorine  with  HC1. 

massive. 

2. 

Brittle. 

6.25 

IV.  Usually 
massive. 

Imperfect. 

Opaque. 

On  charcoal  gives  antimony    coat- 
'   ing  and    globule  of  silver. 

2. 

Brittle. 

5.8 

III.  Also 
massive. 

Conchoidal. 

Translucent. 

Gives   reactions   for    antimony   and 
silver. 

34 


A.     MINERALS  WITH 


Analytical    Key.                          Species. 

Composition. 

Lustre. 

Color. 

Slreak. 

Biotite    (56). 

(KFeMg 

Al)2SiO4. 

Pearly  to 
submetallic. 

Black. 

Gray. 

Micaceous. 

. 

Lepidomelane 

C56). 

(KFeAl)2 
SiO4. 

Adamantine 
to  pearly. 

Black. 

Grayish 
green. 

MaUeable. 

Argentite   (6). 

AgS. 

Metallic. 

Blackish 
lead-gray. 

Blackish 
lead-gray. 

Hematite  (25). 

Fe203. 

Metallic. 

Black  to 

Red. 

gray. 

Streak  red. 

Pyrargyrite 

(15)- 

Ag3SbS3. 

Adamantine 
to  dull. 

Black  to 
cochineal- 
red. 

Cochineal- 
red. 

| 

Streak 
brown. 

Sphalerite  (7). 

ZnS. 

Submetallic. 

Black. 

Brown. 

•S 

i 

a 

Streak 
white  or 

Arsenic  (3). 

As. 

Metallic. 

White. 

White  or 

i 

1s» 

gray. 

gray. 

1 

Streak 

PQ 

o* 

black. 

Mineral  Coal 

C,H,0,  etc. 

Submetallic. 

Black. 

Black. 

| 

G.    I    to    2. 

(84). 

* 

Wad  (32). 

2MnO2 
+H20. 

Dull. 

Black. 

Brownish 
black. 

Manganite  (29). 

Mn203 
+H20. 

Submetallic. 

Iron-black 
to  steel-gray. 

Brownish 
black. 

X  . 

Pyrolusite  (27). 

MnO2. 

Metallic. 

Iron-black 
to  dark  gray. 

Black. 

Streak 

black  or 
nearly  so. 

Chalcocite  (9). 

CuS. 

Metallic. 

Blackish 
lead-gray. 

Blackish 
lead-gray. 

G.  4  to  6. 

Melaconite  (22). 

CuO. 

Metallic 
to  dull. 

Black. 

Black. 

' 

Tetrahedrite 

05)- 

Cu8Sb2S7 

Metallic. 

Dark  gray 
to 
iron-black. 

Dark  gray 
to  black. 

Stephanite  (15). 

Ag5SbS4. 

Metallic. 

Black. 

Black. 

METALLIC     LUSTRE. 


35 


H. 

Tenacity.        G. 

Form. 

Cleavage. 

Properties.           Confirmatory  Chemical  Tests. 

Transparent. 

Elastic  and 

III.  Folia- 

Basal, 

Green  by       [Infusible;    decomposed    by    strong 

2-75 

sectile  J2'9 

ted. 

perfect. 

transmitted       sulphuric  acid. 

light. 

Sectile  to 

III.  Folia- 

Basal, 

Opaque  to 

Fuses    to    magnetic    globule;     de- 

3- 

brittle.  •>' 

ted. 

perfect. 

translucent. 

composed  by  sulphuric  acid. 

2-5 

Malleable 
and  sectile.  7-3 

I.  Also 
massive. 

Uneven. 

Opaque. 

Reactions  for  sulphur;  silver  on 
charcoal. 

4- 

Brittle.            4.9 

III.  Scaly 
or  foliated. 

Basal. 

Opaque. 
Sometimes 
magnetic. 

Infusible;   magnetic   on  charcoal; 
soluble  in  HC1. 

2-5 

Brittle.            5.8 

III.  Also 
massive. 

Conchoidal. 

Translucent 
to  opaque. 

Gives  reactions  for  antimony  and 
silver. 

3-5 

Brittle. 

4- 

I.    Usually 

massive. 

Dodecahe- 
dral,  perfect. 

Opaque. 

Reactions    for  sulphur;   zinc    coat- 
ing    with    soda    on     charcoal; 
effervesces  in  acid  (H2S). 

III.  Mass- 

Ra<;al            \ 

Opaque. 

Volatilizes     without    fusing;      gray 

3-5 

Brittle. 

6. 

ive  or 
botryoidal. 

imperfect. 

Dark  gray 
tarnish. 

fumes  and  coating  on  charcoal; 
metallic  sublimate  in  closed  tube. 

2-5 

Brittle. 

1.5 

Compact  to 
laminated. 

Even  to 
conchoidal. 

Opaque. 

Burns  before  blowpipe;  infusible 
and  insoluble  in  acids. 

3- 

Earthy    to 
brittle. 

3-8 

Amorphous. 

Uneven. 

Opaque. 

Water  in  closed  tube;  amethystine 
bead  with  borax  ;  evolves  chlorine 
with  HC1. 

4- 

Brittle. 

4-3 

IV.  Usually 
acicular  or 
columnar. 

Prismatic, 
perfect. 

Opaque.    . 

Water  in  closed  tube;  amethystine 
bead  with  borax. 

2-5 

Brittle. 

4.8 

IV.  Usually 
columnar  or 

Prismatic. 

' 
„                      Infusible;   amethystine    bead    with 
borax  ;  evolves  chlorine  with  HC1. 

massive. 

Fusible;     blue     flame    with    HC1; 

2-75 

Brittle. 

5-7 

IV.  Often 
massive. 

Prismatic. 

Opaque. 

copper  with  soda  on  charcoal; 
sulphur  reaction. 

3- 

Brittle  to 
earthy. 

6.25 

IV.  Usually 
massive  or 
earthy. 

Uneven  or 
earthy. 

Opaque. 

Infusible;  copper  with  soda  on 
charcoal;  green  solution  with 
nitric  acid. 

3- 

Brittle. 

4.8 

I.  Usually 
massive. 

Uneven. 

Reactions    for    antimony;     copper 
Opaque.             with  soda  on  charcoal. 

i 

2-5 

Brittle. 

6.25 

IV.  Usually 
massive. 

Imperfect. 

Q                    'Reactions  for  antimony;  silver  with 
soda  on  charcoal. 

1 

A.     MINERALS  WITH 


Analytical    Key. 


Species.  'Composition.        Lustre.  Color.  Streak. 


Strongly 
magnetic. 
Malleable. 

h 
[ron   (2).                Fe.                   Metallic. 

ron-gray       |  Iron-gray 
to  black.        to  black. 

Strongly 

magnetic.  Magnetite  (23).  Fe^C^.             Metallic.         Iron-black.     Black. 

Brittle. 

I 

Streak 
black. 
G.  above  7. 

Wolframite                       vyQ 

(40- 

Submetallic. 

brownish       i 
black.: 

Brownish 
black. 

Streak 

, 

black. 
Uncrys- 
talline. 

Psilomelane 

(32). 

Mn°lw  n  Submetallic.  Iron-black.     Br°Wn!S^  t 
-f-rl2U.'                                                               oiacK. 

Menaccanite         (FeTi)2O3. 

(25).! 

...      T        111      !  Brownish 
Submetallic.  Iron-black.                 black 

Streak 
black. 
Crystalline. 

Manganite  (29). 

Mn2O 
+H20. 

Submetallic. 

Iron-black      Brownish 
sted-gray-              **** 

i 

Columbite   (35). 

FeCb2Gv 

Submetallic. 

Iron-black. 

Brownish 
black. 

i 
1 

1 

Brookite  (27).     TiO2.               adamantine 

Black. 

Dark  gray. 

KI 

»5 

Streak 

dark  gray. 

1 

Allanite   (55).       ComP|^atJ  Submetallic. 

Black.             Dark  gray. 

. 

j^J 

i                         ' 

H 

| 

Streak 
brown. 

Sphalerite   (7).    ZnS. 

Resinous  to 
adamantine. 

Black.              Brown. 

H.  4. 

Chromite   (23). 

FeCr2O4. 

Submetallic. 

Iron-black. 

Grayish 
brown. 

Streak 
brown. 

Franklinite(23).kFeZnMn)* 

Metallic.    . 

Iron-black. 

Reddish 
brown. 

H.  5-5- 

; 

Samarskite(35) 

Complex 
columbate 

Submetallic, 
shining 

Reddish 
Black.                        brown> 

Hematite   (25).    Fe2O3. 

Metallic 
to  dull 

Iron-black, 
to 
steel-gray 

Red. 

Streak  red. 

1 

Turgite  (28).       ^^^Q 

Submetallic. 

Reddish 
black 

Red. 

METALLIC    LUSTRE. 


37 


H.        Tenacity. 

G.           Form.            Cleavage. 

Other 
Properties. 

Confirmatory  Chemical  Tests. 

4-5 

Malleable. 

7-5 

I.  Usually 
compact. 

Octahedral; 
usually  none. 

Opaque. 
Strongly 
magnetic. 

Infusible;   soluble  in  HC1. 

5-5 

Brittle. 

I.  Usually 
granular. 

Octahedral. 

Opaque. 
Strongly 
magnetic. 

Infusible;   soluble  in  HC1. 

5-5 

Brittle. 

7-4 

V.  Also 
lamellar 
or  massive. 

Prismatic, 
perfect. 

Opaque. 

Fuses  easily  to  a  magnetic  globule; 
reactions  for  manganese. 

5* 
5- 

Brittle. 

4.2 

Compact 
and    often 
botryoidal. 

Even  or 
conchoidal. 

Opaque. 

Infusible;    water    in    closed   tube; 
evolves  chlorine  with  HC1. 

Brittle. 

4-75 

III.  Often 
laminated. 

None. 

Opaque. 
Otten  slight- 
ly magnetic. 

Infusible;   reactions  for  iron. 

4- 

Brittle. 

4-3 

IV.  Usually 
prismatic   or 
columnar. 

Prismatic, 
perfect. 

Opaque. 
Never   mag- 
netic. 

Infusible;    \vater    in   closed    tube; 
amethystine  bead  with  borax. 

6. 

Brittle. 

6. 

IV.    Crystals 
to  coarsely 
massive. 

Prismatic. 

Opaque. 

Infusible. 

5-5 

Brittle. 

IV.  Square 
crystals. 

Prismatic, 
indistinct. 

Opaque. 

Infusible  and  insoluble. 

5-5 
4- 

Brittle. 

3-6 

V.  Tabular 
and-r 
prismatic. 

In  traces. 

Opaque. 

Fuses     with     intumescence     to     a 
magnetic     globule  ;      gelatinizes 
with  HC1. 

Brittle. 

4- 

I.  Usually 
massive. 

Dodecahe- 
dral,  perfect. 

Opaque. 

Reactions  for  sulphur;   zinc  coating 
with  soda  on  charcoal. 

5-5 

Brittle. 

4-4 

I.  Usually 
massive. 

Vone. 

Opaque. 
Sometimes 
magnetic. 

Infusible;    green  bead  with    borax. 

5-5 

Brittle 

5- 

I.  Octahe- 
drons, also 
massive. 

Indistinct. 

Ooaque. 
Slightly 
magnetic. 

Infusible;   reactions  for  manganese 
and  zinc  with  borax  and  soda. 

5-5 

Brittle. 

5-7 

V.  Also 
massive. 

None. 

Opaque. 

Emerald-green     bead    with     SPh; 
green  bead  with  soda. 

5-5 

Brittle. 

4-9 

III.  Scaly, 
also  massive 
or  botry- 
oidal. 

Basal. 

Opaque. 
Sometimes 
magnetic. 

Infusible;     magnetic  'on    charcoal; 
soluble  in  HC1. 

5- 

Brittle. 

3-7 

Massive  and 
botryoidal 

None. 

Opaque. 

Like  hematite,  but  yields  water   in 
closed  tube. 

A.     MINERALS     WITH 


Analytical  Key. 

Species. 

Composition.        Lustre.               Color. 

Streak. 

(•* 

Gothite  (29). 

Fe2O3 
+H20. 

Adamantine,  Brownish 
imperfect.              black. 

Yellow. 

fe  s 

Streak 

C5  "?! 

yellow. 

006 

Limonite  (30). 

2Fe203 
+3H20. 

Submetallic 
to  silky. 

Brown 
to  black. 

Yellow. 

Magnetite  (23). 

Fe304. 

Metallic. 

Iron-black. 

Black. 

Strongly 

magnetic. 

Emery  (25). 

A1203 
+Fe304. 

Metallic. 

Black  to 
brown. 

Black  to 
brown. 

Streak 

Menaccanite 
(is)- 

(FeTi)203. 

Submetallic. 

Iron-black. 

Brownish 
black. 

black. 

Crystalline. 

Columbite  (35). 

FeCbOe. 

Submetallic. 

Iron-black. 

Brownish 
black. 

Continued 

Streak 
black. 
Uncrys- 
talline. 

Psilomelane 

(32). 

MnO2 
-|-H20. 

Submetallic. 

Iron-black. 

Brownish 
black. 

Streak  gray 

rfi 

or  ^       Cassiterite  (26^. 
brown. 

SnO2. 

Adamantine.  Black. 

Gray  to 
light  brown. 

sj 

1 

G.  about  7. 

1  ' 

1 

Rutile  (26). 

TiO2. 

Metallic  to 
adamantine. 

Black. 

Gray  to 
light  brown. 

Ej      ^ 

Streak  gray 

- 

or  light 
brown. 

Brookite  (27). 

TiO2. 

Metallic  to 
adamantine. 

Black. 

Gray  to 
light  brown. 

G.  about  4. 

Allanite   (55). 

Complex 
silicate. 

Submetallic. 

Black. 

Gray  to 
hgnt  brown. 

Franklinite(23). 

(FeZnMn)3 

Metallic. 

Iron-black. 

Reddish 

Streak    dark 

U4. 

reddish 

brown. 

Samarskite(35)  . 

Complex 
columbate. 

Submetallic, 
shining. 

Black. 

Reddish 
brown. 

Hematite   (25). 

Fe2O3. 

,,  ,   ,,.             Iron-black 
MetalllC'          to  steel-gray. 

Red. 

Streak  red. 

Turgite  (28). 

2Fe2O3 
-r-H2O. 

Submetallic.  !Reddis* 
black. 

Red. 

Compare  Limonite. 

\ 

METALLIC  LUSTRE. 


39 


H. 

5- 

Tenacity,     j    G. 

Form. 

Other 
Cleavage.        Properties. 

Confirmatory  Chemical   Tests. 

Brittle. 

4.2 

IV.  Colum- 
nar,    fibrous 
and  botry- 
oidal. 

;  Prismatic, 
perfect. 

Opaque. 

Water  in  tube;   magnetic  on  char- 
coal. 

Massive,  fi- 

5- 

Brittle. 

3-8 

brous  and 
botryoidal. 

None. 

i  Opaque. 

Like  gothite. 

6.5 

Brittle. 

5- 

I.  Usually 
massive. 

Octahedral. 

Opaque. 
Strongly 
magnetic. 

Infusible;   soluble  in  HC1. 

7109 
6. 

Brittle. 

4-5 
4-75 

III.  Coarsely 
to  finely 
granular. 

None. 

Opaque. 
Strongly         Infusible  and  insoluble, 
magnetic. 

Brittle. 

III.  Often 
laminated. 

None. 

Opaque. 
Often  slight- 
ly magnetic. 

Infusible;    reactions  for  iron. 

6. 

Brittle. 

6. 

IV.  Usually 
in  crystals. 

Prismatic. 

Opaque. 

Infusible. 

6. 
6-5 

Brittle. 

4.2 
6.8 

Compact  or 
botryoidal. 

Even  or 
conchoida]. 

Opaque. 

Infusible;     water    in    closed    tube; 
evolves  chlorine  with  HC1. 

Brittle. 

II.  Also 
massive    and 
botryoidal. 

Imperfect. 

Opaque. 

Infusible;  metallic  tin  with  soda  on 
charcoal. 

6.25    Brittle. 

4-2 

II.  Pris- 
matic and 
twin  crystals. 

Prismatic, 
distinct. 

Opaque. 

Infusible. 

6. 

Brittle. 

4.2 

IV.  Square 
crystals. 

Prismatic, 
indistinct. 

Opaque. 

Like  rutile. 

6. 

Brittle. 

3-6 

V.  Tabular 
and 
prismatic. 

In  traces. 

Opaque. 

Fuses  with  intumescence  to  a  mag- 
netic   globule;     gelatinizes    with 
HC1. 

6.5 

Brittle. 

5- 

I.  Octahe- 
drons and 
massive. 

Indistinct. 

Opaque. 
Slightly 
magnetic. 

Infusible;   reactions   for'  manganese 
and  zinc  with  borax  and  soda. 

6. 

Brittle. 

5-7 

IV.  Also 
massive. 

None. 

Opaque. 

Emerald-green     bead    with     SPh; 
green  bead  with  soda. 

. 

6.5      Brittle. 

4-9 

III.  Scaly, 
also    com- 
pact and 
botryoidal. 

Basal. 

Opaque. 
Sometimes 
magnetic. 

Infusible;     magnetic    on    charcoal; 
soluble  in  HC1. 

6. 

Brittle. 

3-7 

Compact, 
botryoidal 
and  earthy. 

None. 

Opaque. 

Like  hematite;    but  yields  water  in 
closed  tube. 

4o 


A.     MINERALS  WITH 


Analytical    Key. 

Species. 

Composition, 

Lustre.               Color.               Streak. 

Greasy  feel. 

Graphite   (5). 

C. 

Metallic. 

Black  to 
dark  gray. 

Black. 

i  Usually 

foliated. 

Molybdenite 

MoS2. 

Metallic. 

Lead-gray. 

Lead-gray. 

i 

Malleable 
and  sectile. 

Argentite   (6). 

AgS. 

Metallic. 

Blackish 
lead-gray. 

Blackish 
lead-gray. 

c 

-\ 

u. 

i 

M 

Streak 

black. 

Pyrolusite   (27). 

MnO2. 

Metallic. 

Iron  -black 
to  gray. 

Black. 

Stibnite   (13). 

Sb2S3. 

Metallic. 

Light  lead- 
gray. 

Lead-gray. 

Streak  gray. 

Bismuth  (3). 

Bi. 

Metallic. 

Reddish 
white. 

White  to 
gray. 

1 

Malleable 
and  sectile. 

Argentite   (6). 

AgS. 

Metallic. 

Blackish 
lead-gray. 

Blackish 
lead-gray. 

| 

a 

Streak  black. 
Color 
bronze- 

Pyrrhotite  (8). 

Fe7S8. 

Metallic. 

Bronze- 
yellow. 

Grayish 
black. 

^ 

yellow. 

Manganite  (29). 

Mn2O3 
+H20. 

Submetallic. 

Iron-black 
to 
steel-gray. 

Brownish 
black. 

Iron-black 

Streak 
black. 

Pyrolusite   (27;. 

MnO2. 

Metallic. 

to 
steel-gray. 

Black. 

^ 

Color  steel- 

! 

gray   to 
iron-black. 

Tetrahedrite 
(IS)- 

Cu8Sb2S7. 

Metallic. 

Dark  gray 
to 
iron-black. 

Dark  gray 
to  black. 

Melaconite  (22). 

CuO. 

Metallic 

Black  to 

Black. 

to  dull. 

gray. 

Arsenic  (3). 

As. 

Metallic.         Tin-white. 

Gray. 

Streak  gray. 

Color    white 

or  light  gray 

Antimony  (3). 

Sb. 

Metallic. 

Tin-white. 

Gray. 

on  fresh 

surface. 

Bismuth  (3). 

Bi. 

Metallic. 

Reddish 
white. 

W7hite  to 
gray. 

METALLIC     LUSTRE. 


H, 

Tenacity. 

G.            Form.             Cleavage. 

Othei 

Properties. 

Confirmatory  Chemical  Tests. 

1.25 

Sectile. 

2.2 

III.  Usually 
foliated. 

Basal, 
perfect. 

Opaque. 
Greasy  feel. 

Infusible;   unaltered  by  acids. 

1.25 

Sectile. 

4.6 

III.  Usually 
foliated. 

Basal, 
perfect. 

Opaque. 
Greasy  feel. 

Infusible;    reactions  for  sulphur. 

2. 

Malleable 
and  sectile. 

7-3 

I.  Also 
massive. 

Uneven. 

Opaque. 

Reactions  for  sulphur;  silver  on 
charcoal. 

IV.  Usually 

2. 

Brittle. 

4.8 

columnar  or 
massive. 

Prismatic. 

Opaque. 

Infusible;  amethystine  bead  with 
borax;  evolves  chlorine  with  HC1. 

2. 

Brittle. 

4-5 

IV.  Colum- 
nar to 
granular. 

Pinacoidal, 
perfect. 

Opaque. 

Fuses  very  readily  and  gives  an- 
timony fumes  and  coating  on 
charcoal. 

illl    Also 

2. 

Brittle.             9.7     massive   and 
foliated. 

Basal, 
perfect. 

Opaque. 
Tarnishes. 

Fuses  and  volatilizes,  leaving  yel- 
low coating. 

2-5 

Malleable                 I.  Also 
and  sectile.  7  -3    .         massive. 

Uneven. 

i 
Q                      Reactions    for    sulphur;   silver    on 
charcoal. 



I 

i 

3-5 

Brittle. 

4-5 

III.    Usually 
massive. 

Uneven. 

Opaque. 
Tarnishes. 

Fusible  to  magnetic  mass,  usually 
slightly  magnetic  before  fusion. 

4- 

Brittle. 

4-3 

IV.  Usually 
prismatic    or 
columnar. 

Prismatic, 
perfect. 

Opaque. 

Infusible;  water  in  closed  tube; 
amethystine  bead  with  borax. 

IV    Usually 

2-5 

Brittle. 

4-8 

columnar  or 
massive. 

Prismatic. 

Opaque. 

Infusible;  amethystine  bead  with 
borax;  evolves  chlorine  with  HC1. 

3- 

Brittle. 

4-8 

I.  Usually 
massive. 

Uneven. 

Opaque. 

Reactions  for  antimony;  copper 
with  soda  on  charcoal. 

3- 

Brittle  to 
earthy. 

6.25 

IV.  Usually 
massive  or 
earthy. 

Uneven  or 
earthy. 

Opaque. 

Infusible;  copper  with  soda  on 
charcoal;  green  solution  with 
nitric  acid. 

3-5 

Brittle. 

6. 

III.  Massive 
or 
botryoidal. 

Basal, 
imperfect. 

Opaque. 
Dark  gray 
tarnish. 

Volatilizes  without  fusing,  giving 
gray  fumes  and  coating  on  char- 
coal, and  metallic  sublimate  in 
tube. 

3-5 

Brittle. 

III.  Lamel- 
6.6           lar  or 
massive. 

Basal, 
perfect. 

Opaque. 

Fuses  readily  on  charcoal,  giving 
copio-us  white  fumes  and  a  white 
coating. 

Ill    Also 

2-5 

Brittle. 

9.7    [massive  and 
foliated. 

Basal, 
perfect. 

Opaque.          Fuses  and    volatilizes,    leaving  yel- 
Tarnishes.          low  coating  on  charcoal. 

1 

42 


A.     MINERALS     WITH 


Analytical  Key. 

Species. 

Composition.        Lustre. 

Color. 

Streak. 

8 

8 

Streak 

Stibnite   (13). 

Sb2S3. 

Metallic. 

Light 
lead-gray. 

Lead-gray. 

gray. 

a 
\ 

Color  dark 
gray  to 
black  on 

Chalcocite   (9). 

CuS. 

Metallic. 

Blackish 
lead-gray. 

Blackish 
lead-gray. 

*•*» 

fresh 

05 

surface. 

Galenite   (6). 

PbS. 

Metallic. 

Dark 
lead-gray. 

Dark 
lead-gray. 

Strongly 
magnetic. 
Malleable. 

Iron   (2). 

Fe! 

Metallic. 

Iron-gray 
to  black. 

Iron  -gray 
to  black. 

Strongly 

Dark  gray 

magnetic. 

Magnetite  (23). 

Fe304. 

Metallic. 

to            Black. 

Brittle. 

iron-black. 

Marcasite    (n). 

FeSo. 

Metallic. 

Pale 
grayish 

Gravish 
black 

yellow. 

ntimied. 

Streak 
grayish 
black. 
Color  white 

Arsenopyrite 

(u). 

FeAsS. 

Metallic. 

Silver-  white 
to 
steel-gray. 

Grayish 
black. 

t 

1 

• 

to 
light  gray 
on  fresh 
surface. 

Cobaltite   (10). 

CoAsS. 

Metallic. 

Silver-white 
to 
steel-gray. 

Gravish 
black. 

3 

* 

Smaltite   (10). 

(CoFeNi) 

Metallic. 

Tin-white 
to 

Grayish 

black 

3 

1 

As2. 

steel-grayJ 

K* 

e»5 

Streak 
grayish  or 

Pyrrhotite   (8). 

Fe7S8. 

Metallic. 

Bronze- 
yellow. 

Gravish 
black. 

brownish 

black. 
Color 

Marcasite  (n). 

FeS2. 

Metallic. 

Pale 
grayish 

Grayish 

yellowish  or 

yellow. 

>  ack. 

reddish  on 

fresh 
surface. 

Niccolite(S). 

XiAs. 

Metallic. 

Pale 
copper-red. 

Brownish 

black. 

Psilomelane 

MnOa4- 

Submetallic. 

Iron-black 
to 

Brownish 

Streak 

(32). 

.  H2O. 

steel-gray. 

- 

brownish 
black. 
Color  dark 
gray  to 

Manganite 

(29)- 

Mn2O3 
+H20. 

Submetallic. 

Iron-black      Brownish 
steel-gray. 

black. 

Menaccanite 

(FeTi)203. 

Submetallic. 

Iron-black     'Brownish 
to                      black 

(25)- 

steel-gray. 

METALLIC  LUSTRE. 


43 


H. 

Tenacity. 

G. 

Form. 

Cleavage. 

Other 
Properties. 

Confirmatory  Chemical  Tests. 

2-5 

Brittle. 

4-5 

IV.  Colum- 
nar to 
massive. 

Pinacoidal, 
perfect. 

Opaque. 

Fuses  very  readily,  and  gives  an- 
timony fumes  and  coating  on 
charcoal. 

2-75 

Brittle. 

5-7 

IV.  Crystals 
also  massive. 

Prismatic, 
indistinct. 

Opaque. 
Dull  black 
tarnish. 

Fusible;  blue  flame  with  HC1; 
copper  with  soda  on  charcoal; 
sulphur  reactions. 

2-75 

Brittle. 

7-5 

I.  Cubic 
and  massive. 

Cubic, 
perfect. 

Opaque. 

Fusible,  yielding  metallic  lead  and 
sulphur  fumes. 

4-5 

Malleable. 

7-5 

I.  Usually 
compact. 

Usually 
none. 

Opaque, 
Strongly 
magnetic. 

Infusible;   soluble  in  HC1. 

5-5 

Brittle. 

5- 

I.  Usually 
granular. 

Octahedral. 

Opaque. 
Strongly 
magnetic. 

Infusible;   soluble  in  HC1. 

6. 

Brittle. 

4.8 

IV.  Often 
globular, 
etc. 

Prismatic, 
perfect. 

Opaque. 

Magnetic  residue  on  charcoal;  sul- 
phur sublimate  in  tube. 

5-5 

Brittle. 

5.2 

IV.  Also 
massive. 

Prismatic, 
distinct. 

Opaque. 

Arsenic  coating  and  magnetic  resi- 
ue  on  charcoal;  arsenic  subli- 
mate in  tube. 

5-5 

Brittle. 

6.2 

I.  Also 
massive. 

Cubic, 
perfect. 

Opaque. 

Arsenic  fumes  and  coating  on  char- 
coal; cobalt-blue  with  borax. 

5-5 

Brittle. 

7- 

I.  Usually 
massive. 

Cubic, 
in  traces. 

Opaque. 

Arsenic  coating  and  magnetic  resi- 
due on  charcoal;  arsenic  sublimate 
in  tube. 

4-5 

Brittle. 

4-5 

III.  Usually 
massive. 

Uneven. 

Opaque. 
Tarnishes. 

Fusible  to  magnetic  mass;  usually 
slightly  magnetic  before  fusion. 

6. 

Brittle. 

4.8 

IV.  Often 
globular, 
etc. 

Prismajic, 
perfect. 

Opaque. 

Magnetic  residue  on  charcoal;  sul- 
phur sublimate  in  tube. 

5-25 

Brittle. 

7-5' 

III.  Usually 
massive. 

Uneven. 

Opaque. 

Arsenic  fumes  and  coating  and  mag- 
netic globule  on  charcoal. 

5- 

Brittle. 

4.2 

Compact 
and  often 
botryoidal. 

Even  or 
conchoidal. 

Opaque. 

Infusible;  water  in  closed  tube; 
evolves  chlorine  with  HC1. 

4- 

Brittle. 

4-3 

IV.  Usually 
prismatic 
or  columnar. 

Prismatic, 
perfect. 

Opaque. 

Infusible;  water  in  closed  tube; 
amethystine  bead  with  borax. 

5- 

Brittle. 

4-75 

III.  Often 
laminated. 

None. 

Opaque. 
3ften  slight- 
ly magnetic. 

Infusible;   reactions  for  iron. 

A.     MINERALS    WITH 


Analytical  Key.                          Species.             Composition. 

Lustre. 

Color. 

Streak. 

Chromite  (23). 

FeCr2O4. 

Submetallic. 

Iron-black 
to  dark 

Grayish 
brown. 

Streak 

gray. 

ii 

brown. 

Franklinite  (23)  . 

(FeZnMn)3 
04. 

Metallic. 

Iron-black 
to   dark 
gray. 

Reddish 
brown. 

Streak  red. 

Hematite   (25). 

Fe203. 

Metallic. 

\ 
Steel-gray  to  „    , 
iron  black.  Red" 

Iron-black 

Magnetite  (23). 

Fe304. 

Metallic. 

to  dark      Black. 

Strongly 

gray. 

magnetic. 

Emery  (25). 

A1203+ 
Fe804. 

Metallic. 

Iron-black      Black  to 
to  brown.            brown. 

Marcasite  (n). 

FeS2. 

Metallic. 

Pale  grayish 
yellow. 

Grayish 
black. 

"tt 

Streak 

•1 
8 

grayish 
black. 
Color  white, 

Arsenopyrite 

(n). 

FeAsS. 

Metallic. 

Silver-white 
to  steel-gray. 

Gravish 
black. 

a 

gray  or 

>i 
1 

grayish 
yellow,  on 
fresh 

Cobaltite  (10). 

CoAsS. 

Metallic. 

Silver-white 
to  steel-gray. 

Grayish 
black. 

?» 

surface. 

I 

§ 

i 

Smaltite  (10). 

(CoFeNi) 

As,. 

Metallic. 

Tin-white  to 
steel-gray. 

Grayish 
black. 

P 

$ 

i 

Streak 
brownish 
black. 

Psilomelane 

(32). 

Mn02 
+H20. 

Submetallic. 

Iron-black 
to  steel-gray. 

Brownish 

black. 

^ 

Color   dark 

gray  to 
black. 

Menaccanite 

/"--X 

(FeTi)203. 

Submetallic. 

Iron-black 
to  steel-gray. 

Brownish 
black. 

(25)- 

Streak  light 

gray  or 
brown. 

Cassilerite  (26). 

SnO2. 

Adamantine. 

Gray  to 
black. 

Light  gray 
or  brown. 

G.  about  7. 

Streak  light 

gray   or 
brown. 

Rutile  (26). 

Ti02. 

Adamantine. 

Brown  to 
gray. 

Light    gray 
or  brown. 

G.  about  4. 

Streak  dark 
reddish 
brown. 

Franklinite  (23). 

(FeZnMn)3 
04. 

Metallic. 

Iron-black 
to    dark 
gray. 

Reddish 
brown. 

\  . 

• 

Streak  red. 

Hematite  (25). 

Fe2O3. 

Metallic. 

Steel-gray  to 
iron-black. 

Red. 

METALLIC    LUSTRE. 


45 


H. 

5-5 

Tenacity. 

G.   1         Form. 

Cleavage. 

Other 
Properties. 

Confirmatory  Chemical  Tests. 

Brittle. 

44 

I.  Usually 
massive. 

None. 

Opaque. 
Sometimes 
magnetic. 

Infusible;   green  bead  with    borax. 

5-5 

Brittle. 

5- 

I.  Octahe- 
drons, also 
massive. 

Indistinct. 

3paque. 
Slightly 
magnetic. 

Infusible;   reactions  for  manganese 
and  zinc  with  borax  and  soda. 

5-5 

Brittle. 

4-9 

5- 

III.  Scaly, 
massive  or 
botryoidal. 

Basal. 

Opaque. 
Sometimes 
magnetic. 

Infusible;      magnetic  on  charcoal; 
soluble  in  HC1. 

6.5 

Brittle. 

I.  Usually 
granular. 

Octahedral. 

Opaque. 
Strongly 
magnetic. 

Infusible;   soluble  in  HC1. 

7109 

Brittle. 

4-5 

III.   Usually 
granular. 

None. 

Opaque. 
Strongly 
magnetic. 

Infusible  and  insoluble. 

6.5 

Brittle. 

4.8 

IV.  Often 
globular,  etc. 

Prismatic, 
perfect. 

Opaque. 

Magnetic  on  charcoal  ;  sulphur  sub- 
limate in  closed  tube. 

6. 

Brittle. 

6.2 

IV.  Also 
massive. 

Prismatic, 
distinct. 

Opaque. 

Arsenic  coating  and  magnetic  resi- 
due on  charcoal;    arsenic    subli- 
mate in  tube. 

6. 

Brittle. 

6.2 

I.  Also 
massive. 

Cubic, 
perfect. 

Opaque. 

Arsenic  fumes  and  coating  on  char- 
coal;  cobalt-blue   with  borax. 

I 

6. 

Brittle. 

7- 

1.  Usually 
massive. 

Cubic, 
in    traces. 

Opaque. 

Arsenic  coating  and  magnetic  resi- 
due on  charcoal;    arsenic    subli- 
mate in  tube.                     « 

6. 

Brittle. 

4.2 

Compact 
and   often 
botryoidal. 

Even  or 
conchoidal. 

Opaque. 

Infusible;   water  in    closed     tube; 
evolves  chlorine  with  HC1. 

6. 

Brittle. 

4-75 

III.  Often 
laminated. 

None. 

Opaque. 
Often  slight- 
ly magnetic. 

Infusible;   reactions  for  iron. 

6.5 

Brittle. 

6.8 

II.  Also 
massive  and 
botryoidal. 

Imperfect. 

Opaque. 

Infusible;   metallic  tin     with    soda 
on  charcoal. 

6.25 

Brittle. 

4.2 

5- 
4.9 

11.  Pris- 
matic and 
twin  crystals. 

Prismatic, 
distinct. 

Opaque. 

Infusible. 

6.5 

Brittle. 

I.  Octahe- 
drons, also 
massive. 

Indistinct. 

Opaque. 
Slightly 
magnetic. 

Infusible;   reactions  for  manganese 
and  zinc  with  borax  and  soda. 

6.5 

Brittle. 

III.    Scaly, 
massive  or 
botryoidal. 

Basal. 

Opaque. 
Sometimes 
magnetic. 

Infusible;   magnetic    on    charcoal; 
soluble  in  HC1. 

46 


A.     MINERALS  WITH 


Analytical    Key.                         Species.             Composition. 

Lustre. 

Color.               Streak. 

! 

Liquid. 

Mercury  (2). 

Ag- 

\ 
Metallic.         Tin-white.      White. 

•| 

Brittle. 

Bismuth   (3). 

Bi. 

Metallic. 

Reddish 
white.  Gra>'' 

Malleable. 

Silver  (i). 

Ag- 

Metallic. 

Silver-white.  White. 

Arsenic  (3). 

As. 

Metallic. 

Tin-white. 

White. 

i 

Brittle. 

Antimony  (3). 

Sb. 

Metallic. 

Tin-white. 

White. 

* 

Bismuth  (3). 

Bi. 

Metallic. 

Reddish 

white. 

Gray. 

Malleable. 

Silver  (i). 

Ag. 

Metallic. 

Silver-white.  White. 

1 

Ife 

1 

Ortho- 
rhombic. 

Arsenopyrite 

(n). 

FeAsS. 

Metallic. 

Silver-white   Gfayish 
steel-gray.             black' 

^ 

'  1 

Cobaltite  (10). 

CoAsS. 

Metallic. 

Silver-white 
to 
steel-gray. 

Grayish 
black. 

CO 

Isometric. 

i 

• 

Smalite  (10). 

(CoFeNi) 

As2 

Metallic. 

Tin-white 
to 
steel-gray. 

Grayish 
black. 

Ortho- 
rhombic. 

Arsenopyrite 

(n). 

FeAsS. 

Metallic. 

Silver-white 
to 
steel-gray. 

Grayish 
black. 

Cobaltite   (10). 

CoAsS. 

Metallic. 

Silver-white 
to 

Grayish 
black 

S 

Isometric. 

steel-gray. 

Smaltite   (10). 

(CoFeNi) 
As.2 

Metallic. 

Tin-white 
to 
steel-gray. 

Grayish 
black. 

METALLIC  LUSTRE. 


47 


H. 

Tenacity. 

G  . 

Form. 

Cleavage. 

Other 
Properties. 

Confirmatory  Chemical  Tests. 

Liquid. 

*3-5 

globules. 

None. 

Opaque. 

Volatile;   dissolves  in  nitric  acid. 

2. 

Brittle. 

9-7 

III.  Also 
massive   and 
foliated. 

Basal, 
perfect. 

Opaque. 
Tarnishes. 

Fuses  and  volatilizes,  leaving  yel- 
low coating  on  charcoal. 

I.  Grains, 

Opaque. 

2.5     Malleable. 

10.  s 

scales  and 

None. 

Tarnishes 

Infusible;   soluble  in  nitric  acid. 

threads. 

black. 

3-5 

Brittle. 

6. 

III.  Massive 
and  botry- 
oidal. 

Basal, 
imperfect. 

Opaque. 
Dark  gray 
tarnish. 

Volatilizes  without  fusing;  gray 
fumes  and  coating  on  charcoal, 
and  metallic  sublimate  in  tube. 

3-5 

Brittle. 

6.6 

III.  Lamel- 
lar or 
massive. 

Basal, 
perfect. 

Opaque. 

Fuses  readily  on  charcoal,  giving 
copious  white  fumes  and  coating. 

2-5 

Brittle. 

9-7 

III.  Also 
massive   and 
foliated. 

Basal, 
perfect. 

Opaque. 
Tarnishes. 

Fuses  and  volatilizes,  leaving  yel- 
low, volatile  coating  on  charcoal. 

3. 

Malleable. 

10.5 

I.  Grains, 
scales  and 

None. 

Opaque. 
Tarnishes 

Fusible;   soluble  in  nitric  acid. 

threads. 

black. 

5-5 

Brittle. 

6.2 

IV.  Crystals 
and  massive. 

Prismatic, 
•  distinct. 

Opaque. 

Arsenic  coating  and  magnetic  resi- 
due on  charcoal;  arsenic  subli- 
mate in  tube. 

5-5 

Brittle. 

6.2 

I.  Crystals 
and  massive. 

Cubic, 
perfect. 

Opaque. 

Arsenic  fumes  and  coating  on  char- 
coal; blue  bead  with  borax. 

5-5 

Brittle. 

7- 

I.  Usually 

Cubic, 
in    traces. 

Opaque. 

Like  arsenopyrite;  but  blue  bead 
with  borax. 

6. 

Brittle. 

6.2 

IV.  Crystals 
and  massive. 

Prismatic, 
distinct. 

Opaque. 

Arsenic  coating  and  magnetic  resi- 
due on  charcoal;  arsenic  subli- 
mate in  tube. 

5-5 

Brittle. 

6.2 

I.  Crystals 
and  massive. 

Cubic, 
perfect. 

Opaque. 

Arsenic  fumes  and  coating  on  char- 
coal; blue  bead  with  borax. 

6. 

Brittle. 

I.  Usually 
massive. 

Cubic, 
in  traces. 

Opaque. 

Like  arsenopyrite;  but  blue  bead 
with  borax. 

B.     MINERALS  WITH 


Analytical    Key. 

Species. 

Composition. 

Lustre. 

Color. 

Streak. 

Turgite  (Red 

Ochre)    (28). 
Compare  Hematite 
and  red  Kaolinite. 

2Fe2O3+ 
H20. 

Dull. 

Red. 

Red. 

Realgar  (12). 

AsS. 

Resinous. 

Aurora-red. 

Orange  to 
aurora-red. 

Streak  red. 

Proustite  (15). 

Ag3AsS3. 

Adamantine 
to  dull. 

Cochineal- 
red. 

Cochineal- 
red. 

- 

i 

3yrargyrite 

(15)- 

Ag3SbS3. 

Adamantine 
to  dull. 

Black  to 
cochineal- 
red. 

Cochineal- 
red. 

ss 

1 

k 
o 

"a 

1 

Cinnabar  (8). 

G.  varies  with   im- 
purity from  3  to  9- 

HgS. 

Adamantine 
to  dull. 

Cochineal- 
red 
to  brown. 

Scarlet. 

Streak 
yellow  to 
brown. 

Limonite     (Yel- 
o\v  Ochre)  (30). 

2Fe2O3-f 
3H20. 

Dull. 

Brown  to 
yellow. 

Light  brown 
to  yellow. 

Streak 
dark  brown 
to  black. 
G.  I  to  1.5 

Asphaltum  (84)  . 

Mineral  Coal 

(84). 

C,H,O,  etc. 
C,H,O.  etc. 

Resinous, 
ilesinous. 

Brownish 
black  to 
black. 

Brown  to 
black. 

Dark 
brown. 

Dark 
brown. 

I 

Streak 
dark  brown 
to  black. 
G.  3  to  4. 

Wad  (32). 

2MnO2 
-}-H20. 

Dull. 

Brownish 
black. 

Brownish 
black. 

Streak  bright 
yellow 
to  orange. 

Zincite  (21). 

ZnO. 

Sub- 
adamantine. 

Red  to 
orange. 

Orange 
to   yellow. 

Streak  yel- 
ow  to  brown. 
Compact 
or   fibrous. 

Limonite  (30). 

Compare  Gothite. 

2Fe2O3-|- 
3H20. 

Submetallic 
to  dull. 

Dark  brown 
to  yellow. 

Yellow 
to  brown. 

Turgite  (28). 

2Fe203+ 
H2O 

Submetallic 
to  dull. 

Red  to 
black. 

Red. 

Stre  ak   red. 
Become 
magnetic 
on  charcoal 

Hematite  (25). 
Cuprite  (20). 

Fe203. 
Cu2O. 

Metallic 
to  dull 

Adamantine 
to  dull 

Red  to 

black. 

Red  to 
brown. 

Red. 

Red 
to  brown. 

Cinnabar  (8). 

HgS. 

Adamantine 
to  dull. 

Cochineal- 
red  to 
brown 

Scarlet. 

NON-METALLIC  LUSTRE. 


49 


H. 

Tenacity. 

G. 

3-5 

Form. 

Cleavage. 

Other 
Properties. 

Confirmatory  Chemical  Tests. 

I. 

Earthy. 

Compact. 

Earthy. 

Opaque. 

Water  in  tube;  •  black  and  mag- 
netic on  charcoal. 

'•75 

Brittle. 

3-5 

V.  Also 
massive. 

Clinopina- 
coidal  and 
basal. 

Transparent 
to 
translucent. 

Volatile  and  combustible,  burning 
with  a  blue  flame  and  arsenical 
odor. 

2. 

Brittle. 

5-5 

III.  Also 
massive. 

Conchoidal. 

Translucent 
to  opaque- 

Reactions  for  arsenic  and  silver. 

2. 

Brittle. 

5.8 

III.  Also 
massive. 

Conchoidal. 

Translucent 
to  opaque. 

Reactions  for  antimony  and  silver. 

2. 

Brittle   to 
sectile. 

9- 

III.  Usually 
massive. 

Uneven. 

Usually 
opaque. 

Volatile;  with  soda  in  tube  a  sub- 
limate of  mercury. 

I. 

Earthy. 

3-5 

Compact. 

Earthy. 

Opaque. 

Water  in  tube  ;  black  and  magnetic 
on  charcoal. 

«-5 

Brittle  to 
flexible. 

i-3 

Amorphous. 

Conchoidal. 

Opaque. 

Fuses  and  burns  with  flame. 

«-S 

Brittle. 

1.25 

Amorphous, 
often 
laminated. 

Even  or 
conchoidal. 

Opaque. 

Infusible;  but  readily  ignited,  burn- 
ing with  flame. 

4- 

Earthy. 

3-8 

Amorphous 

Earthy. 

Opaque. 

Water  in  closed  tube;  amethystine 
bead  with  borax;  evolves  chlorine 
with  HC1. 

Brittle. 

5-5 

III.  Also 
massive. 

Basal, 
perfect 

Usually 
opaque. 

Infusible;  soluble  in  acid;  zinc 
coating  with  soda  on  charcoal. 

3- 

Brittle. 

3-8 

Compact, 
fibrous  and 
botryoidal. 

None. 

Opaque. 

Water  in  closed  tube;  black  and 
magnetic  on  charcoal. 

3- 

Brittle. 

3-7 

Compact 
and  botry- 
oidal. 

None. 

Opaque. 

Infusible;  water  in  tube;  magnetic 
on  charcoal. 

3- 

Brittle. 

4-9 

III.  Scaly, 
also   com- 
pact and 
botryoidal. 

Basal. 

Opaque. 
Sometimes 
magnetic. 

Like  turgite;  but  no  water  in  tube. 

3-5 

Brittle. 

6. 

I.  Also  cap- 
illary and 
massive. 

Octahedral. 

Transparent 
to  opaque. 

Colors  flame  green  and  fuses  readily, 
yielding  metallic  copper;  becomes 
magnetic  when  impure. 

2-5 

Brittle  to 
sectile. 

9- 

III.  Usually 
massive. 

Uneven. 

Usually 
opaque. 

Volatile;  with  soda  in  closed  tube 
yields  sublimate  of  mercury;  be- 
comes magnetic  when  impure. 

B.     MINERALS     WITH 


Analytical  Key. 

Species. 

Composition. 

Lustre. 

Color. 

Streak. 

Proustite  (15). 

Ag3AsS3. 

Adamantine 
to  dull. 

Cochineal- 
red. 

Cochineal- 
red. 

Streak  red. 
Not  mag- 
netic on 
charcoal. 

Pyrargyrite 

(IS)- 

Cuprite  (20). 

Ag3SbS3. 
Cu2O. 

Adamantine 
to   dull. 

Adamantine 
to  dull. 

Black  to 
cochineal- 
red. 

Red  to 
brown. 

Cochineal- 
red. 

Red  to 

brown. 

* 

6 
{. 

Cinnabar  (8). 

HgS. 

Adamantine 
to  dull. 

Cochineal- 
red  to 
brown. 

Scarlet. 

Wad  (32). 

2MnO2 
+H20. 

Dull. 

Brownish 
black. 

Brownish 
black. 

1 

Streak 
dull  brown 
to  black. 

Siderite  (44). 

FeC03. 

Vitreous 
to  dull. 

Gray  to 
dark  brown. 

Gray  to 
brown. 

1. 

1 

t. 

Q 

Sphalerite.    (7). 

ZnS. 

Resinous. 

Brown  to 
black. 

Yellow  to 
brown. 

Streak  bright 
yellow  to 
orange. 

Zincite.  (21). 

ZnO. 

Sub- 
adamantine. 

Deep  red 
to  orange. 

Orange- 
yellow. 

Streak  yel- 
low to 
brown. 
Compact  or 
fibrous. 

Limonite  (30). 
Gothite  (29). 

2Fe2O3 

Fe2O3 

+H20. 

Submetallic 
to  dull. 

Adamantine 
to  dull. 

Brown  to 
black. 

Brown  to 

black. 

Yellow  to 
brown. 

Yellow  to 
brown. 

Turgite  (28). 

2Fe2O3-|- 
H20. 

Submetallic 
to  dull. 

Reddish 
black. 

Red. 

1 

Streak 
bright  red. 

Hematite  (25). 
Cuprite  (20). 

Fe2O3. 
Cu2O. 

Metallic 
to  dull. 

Submetallic 
to  dull. 

Reddish 
black  to 
steel-gray. 

Red  to 

brown. 

Red. 

Red  to 
brown. 

Cinnabar  (8). 

HgS. 

Adamantine 
to  dull. 

Cochineal- 
red  to 
brown. 

Scarlet. 

Streak 
reddish 
brown. 
H.  4. 

Sphalerite  (7). 

ZnS. 

Resinous. 

Brown  to 
black. 

Yellow   to 
brown. 

NON-METALLIC     LUSTRE. 


H. 

2-5 

Tenacity. 

G. 

Form. 

Cleavage.       Properties.           Confirmatory  Chemical  Tests. 

Brittle. 

3-7 

III.  Also 
massive. 

Conchoidal. 

Translucent 
to   opaque 

Reactions  for  arsenic  and  silver. 

2-5 

Brittle. 

4-9 

III.  Also 
massive. 

Conchoidal. 

Translucent 
to  opaque. 

Reactions  for  antimony  and  silver. 

3-5 

Brittle. 

6. 

I.  Also 
capillary 
and  massive. 

Octahedral. 

Translucent 
to  opaque. 

j  Colors  flame  green  and  fuses  read- 
i     ily,  yielding  metallic  copper. 

2-5 

Brittle  to 
sectile. 

9- 

III.  Usually 
massive. 

Uneven. 

Usually 
opaque. 

Volatile;   with  soda  in  closed  tube 
yields  sublimate  of  mercury. 

3- 

Earthy. 

3-8 

Amorphous. 

Earthy. 

Opaque. 

Water  in  closed  tube;   amethystine 
bead    with  borax;   evolves    chlo- 
rine with  HC1. 

3-5 

Brittle. 

3-8 

III.  Also 
compact. 

Rhombohe- 
dral,  perfect 

Translucent 
to  opaque. 

Infusible;    blackens    and    becomes 
magnetic  ;  effervesces  in  hot  acid. 

3-5 

Brittle. 

4- 

I.  Also 
massive. 

Dodecahe- 
dral,  perfect 

Translucent 
to  opaque. 

Reactions  for  sulphur;     zinc    coat- 
ing with  soda  on  charcoal. 

4-5 

Brittle. 

5-5 

III.  Also 
massive. 

Basal, 
perfect. 

Usually 
opaque. 

Infusible;     soluble    in     acid;     zinc 
coating  with  soda  on  charcoal. 

5-25 

Brittle. 

4- 

Compact, 
Botryoidal, 
fibrous,  etc. 

Uneven, 
splintery, 
etc. 

Opaque. 

Water  in  closed  tube;  magnetic  on 
charcoal. 

5-25 

5- 

Brittle. 

4.2 

IV.  Usually 
massive, 
fibrous  or 
botryoidal. 

Prismatic, 
perfect. 

Opaque. 

Like  limonite. 

Brittle. 

3-7 

Massive  and 
botryoidal. 

Jneven. 

Opaque. 

Water  in    tube;  magnetic  on  char- 
coal. 

5-5 

Brittle. 

4-9 

III.  Scaly, 
also  massive 
or  botryoid- 
al. 

Basal. 

Opaque. 
Sometimes 
magnetic. 

Infusible;     magnetic  on    charcoal; 
soluble  in  HC1. 

4- 

Brittle. 

6. 

'..  Also  cap- 
illary and 
massive. 

Octahedral. 

Translucent 
to  opaque. 

Colors  frame  green  and  fuses  read- 
ily, yielding  metallic  copper. 

4- 

Brittle  to 
sectile. 

9- 

III.  Usually 
massive. 

Uneven. 

Jsually 
opaque. 

Volatile;   with  soda  in  closed  "tube 
yields  sublimate  of  mercury. 

4- 

Brittle. 

4- 

!.  Usually 
massive. 

Dodecahe- 
dral,  perfect. 

Translucent 
to  opaque. 

Reactions    for    sulphur    and    zinc; 
soluble  in  acid  with  effervescence. 

52 


B.     MINERALS  WITH 


'     Analytical    Key. 

Species. 

Composition. 

Lustre. 

Color. 

Streak. 

Psilomelane 

(32). 

MnO2 
+  H2O. 

Submetallic.  \ 

iron-black. 

Brownish 
black. 

Streak  dark 

\flenaccanite 

CFeTi)203. 

Submetallic. 

[ron-black. 

Brownish 
black 

reddish 

(25)- 

brown  to 

$ 

black. 
rl.    above  5. 

Samarskite(35). 

Complex 
columbate. 

Submetallic, 
shining. 

Black. 

Reddish 
brown. 

s 

i 

l 

i 

Wolframite  (41). 

Compare  Mangan  ite 

(FeMn) 
WO4. 

Submetallic. 

Brownish 
black. 

Brownish 
black. 

'H 

and  Columbtte. 

3 

Siderite  (44). 

FeC03. 

Vitreous. 

Gray  to 
dark  brown. 

Gray  to 
brown. 

Streak 
grayish 

Sphalerite  (7). 

ZnS. 

Resinous. 

Brown  to 
black. 

Yellow  to 
.   brown. 

. 

brown. 

1 

Chromite  (23). 

FeCr2O4. 

Submetallic. 

Iron-black. 

Grayish 
brown. 

1 

1 

Streak 
bright  red 
G.  3.6 

Turgite  (28). 

2Fe2O3 
+H20. 

Submetallic. 

Reddish 
black. 

Red. 

Streak  pale 

0 

red  or 
brown 

Quartz  (Ferrugi-  SiO2 
nous  quartz,    and        -f-Fe2C>3. 

Vitreous 
to  dull. 

Red 
to   brown. 

Light   red 
to  brown. 

«l 

G.  2.6 

Jasper)  (33  1. 

>§ 

Rutile  (26). 

TiO2. 

Adamantine. 

Brown. 

Light 
brown. 

«J 

Streak  pale 

K 

brown 

i 
i 

G.  above  4 

Cassiterite(26). 

SnO,. 

Adamantine. 

Brown  to 
black. 

Gray  to 
light  brown. 

Compare    Chromite.  \ 

i 

Psilomelane 

(32) 

2  H20 

Submetallic. 

Iron-black. 

Brownish 
black. 

Streak  dark 
reddish 

Menaccanite 

(25) 

(FeTi)203. 

Submetallic. 

Iron-black. 

Brownish 
black. 

brown 

to  black 

Samarskite 

(35) 

Complex 
columbate 

Submetallic, 
shining 

Black. 

Reddish 
brown. 

Brownish 

Columbite  (35) 

FeCb2O6. 

Submetallic. 

Black. 

black. 

NON-METALLIC    LUSTRE. 


53 


H. 

Tenacity. 

G.           Form  . 

Cleavage. 

Other 

Properties. 

Confirmatory  Chemical  Tests. 

5- 

Brittle. 

4-2 

Compact 
and  botryoi- 
dal. 

Even  or 
conchoidal. 

Opaque. 

Infusible;     water    in    closed   tube; 
evolves  chlorine  with  HC1. 

5- 

Brittle. 

4-75 

III.  Often 
laminated. 

None. 

Opaque. 
Often  slight- 
ly magnetic. 

Infusible;   reactions  for  iron. 

5-5 

Brittle. 

5-7 

IV.  Also 
massive. 

tfone. 

Opaque. 

Emerald-green    bead     with     SPh; 
green  bead  with  soda. 

5-25 

Brittle. 

7-4 

V.  Also  lam- 
ellar  or 
massive. 

Prismatic, 
perfect. 

Opaque. 

Fuses  easily  to  a  magnetic  globule; 
reactions  for  manganese. 

4-5 

Brittle. 

3-8 

III.  Also 
compact. 

Rhombohe- 
dral,  perfect. 

Translucent 
to  opaque. 

Infusible;     blackens    and   becomes 
magnetic;   effervesces  in  hot  acid. 

4- 

Brittle. 

4- 

1.  Also 
massive. 

Dodecahe- 
dral,  perfect. 

Translucent 
to  opaque. 

Reactions    for  sulphur;    zinc    coat- 
ings with  soda  on  charcoal;  effer- 
vesces in  acid  (H2S). 

5-5 

Brittle. 

4.4 

I.  Usually 
massive. 

None. 

Opaque. 
Sometimes 
magnetic. 

Infusible;    green  bead  with  borax. 

6. 

Brittle. 

3-7 

Compact 
and  botry- 
oidal. 

Uneven. 

Opaque. 

Infusible;     magnetic    on   charcoal; 
soluble  in  HC1;  water    in    closed 
tube. 

7- 

Brittle. 

2.6 

III.  Often 
massive   or 
compact. 

None. 

Translucent 
to  opaque. 

Infusible  and  insoluble. 

6.25 

Brittle. 

4.2 

II.  Pris- 
matic and 
twin  crystals. 

Prismatic, 
distinct. 

Translucent 
to  opaque. 

Infusible  and  insoluble. 

6-5 
6. 

Brittle. 

6.8 

II.  Also 
massive  and 
botryoidal. 

Imperfect. 

Translucent 
to  opaque. 

Infusible;   yields   metallic   tin   with 
soda  on  charcoal. 

Brittle. 

4.2 

Compact  and 
botryoidal. 

Even  or 
conchoidal 

Opaque. 

Infusible;    water    in    closed    tube; 
evolves  chlorine  with  HC1. 

6. 

Brittle. 

4-75 

III.  Often 
laminated. 

iNone. 

Opaque. 
Often  slight- 
ly magnetic. 

Infusible;    reactions  for  iron. 

6. 

Brittle. 

5-7 

IV.  Also 
massive 

Uneven  or 
conchoidal. 

Opaque. 

Emerald-green     bead     with     SPh; 
green  bead  with  soda. 

6. 

Brittle. 

6. 

IV.  Usually 
in  crystals. 

Prismatic. 

Opaque. 

Infusible. 

54 


B.     MINERALS     WITH 


Analytical  Key. 

Species. 

Composition.        Lustre. 

Color.                Streak. 

Sulphur  (4). 

s. 

Resinous. 

Yellow. 

Yellow. 

G.  2  to  2.5 

1 

Kaolinite  (Yel- 
low Clay)    (78). 

ALSi2O7 
+2H2O. 

Dull. 

Yellow. 

Yellow. 

1 

Limonite  (Yel- 
low Ochre)  (30). 

2Fe2O3 
+3H20. 

Dull. 

Yellow. 

Yellow. 

G.  3.5  to  4. 

Orpiment  (13). 

Compare  Realgar. 

As2S3. 

Resinous 
to   pearly. 

Yellow. 

Yellow. 

Streak  bright 
yellow  to 
orange. 

Zincite  (21). 

ZnO. 

Sub- 
adamantine. 

Red  to 
orange. 

Orange  to 

yellow. 

Streak  pale 

Wulfenite  (41). 

PbMoO4. 

Resinous  to 
adamantine. 

Yellow. 

Yellowish 
white. 

yellow. 

1 

IS. 

G.  6  to  7. 

Vanadinite(36). 

Compare  Pyromor- 
ph  ite  and  Mim  etitc. 

3Fb8V208 

+PbCl2. 

Resinous 
to  dull. 

Brown  to 
yellow. 

Yellowish. 

1^ 

5* 

1 

c§ 

ccj 

Sphalerite  (7). 

ZnS. 

Resinous. 

Yellow  to 
brown. 

Yellowish 
brown. 

Streak 

3 

yellow  to 
brown. 

Siderite   (44). 

FeC03. 

Vitreous 
to  dull. 

Gray  to 
dark  brown. 

Gray  to 
brown. 

G.  3  to  4. 

Limonite    (30). 

2Fe2O3 
+3H2O. 

Submetallic 
to  dull. 

Dark  brown 
to  yellow. 

Yellow   to 
brown. 

Compare  Gotkite. 

Streak  bright 
yellow  to 
orange. 

Zincite  (21). 

ZnO. 

Sub- 
adamantine. 

Red  to 
orange. 

Orange  to 
yellow. 

Sphalerite   (7). 

ZnS. 

Resinous. 

Yellow 
to  brown. 

Yellowish 
brown. 

« 

Siderite   (44). 

FeC03. 

Vitreous 
to  dull. 

Gray  to 
dark  brown. 

Gray  to 
brown. 

™ 

Streak 

o£ 

yellow  to 

brown. 

Limonite  (30). 

2Fe.203 
+3H20. 

Submetallic 
to  dull. 

Brown  to 
black. 

Yellow  to 

brown. 

Gothite  (29). 

Fe2O3 
+H20. 

Adamantine 
to  dull. 

Brown  to 
black. 

Yellow  to 
brown. 

NON-METALLIC  LUSTRE. 


55 


H.         Tenacity. 

G.           Form. 

Cleavage. 

Other 

Properties. 

Confirmatory  Chemical  Tests. 

2. 

Brittle. 

2. 

IV.  Often 
massive. 

Imperfect. 

Translucent. 
Electric  by 
friction. 

Burns   with  a   blue  flame  and  sul- 
phurous odor. 

I. 

Plastic  to 
earthy. 

2-5 

IV.  Usually 
compact  or 
clayey. 

Earthy.          'Opaque. 

Infusible   and   insoluble;    water   in 
tube. 

I. 

Earthy. 

3-7 

Earthy. 

None. 

Opaque. 

Black    and    magnetic  on  charcoal; 
water  in  closed  tube. 

2. 

Sub-sectile. 

3-5 

IV.  Usually 
foliated    or 
massive. 

Macropina- 
coidal, 
perfect. 

Translucent. 

Volatilizes;   and  gives  reactions  for 
arsenic  and  sulphur. 

4- 

Brittle. 

5-5 

III.  Also 
massive. 

Basal, 
perfect. 

Usually 
opaque. 

Infusible  ;    zinc  coating  with   soda 
on  charcoal;   soluble  in  acid. 

3- 

Brittle. 

6.5 

II.  Very  thin 
tabular  crys- 
tals. 

Octahedral, 
distinct. 

Translucent. 

\ 
Fuses  readily;   and  yields  lead  with  ] 
soda  on  charcoal. 

3- 

Brittle. 

* 

III.  Usually 
incrusting. 

None. 

Translucent 
•to  opaque. 

Fuses  readily;  yields  lead  with  soda 
on     charcoal;     and       reacts    for 
chlorine  with  copper  oxide.          / 

3-5 

Brittle. 

4- 

I.  Usually 
massive. 

Dodecahe- 
dral,  perfect. 

Translucent 
to  opaque. 

Reactions  for  sulphur;  zinc  coating 
with  soda  on  charcoal. 

3-5 

Brittle. 

3-8 

III.  Also 
compact. 

Rhombohe- 
dral,  perfect. 

Translucent 
to  opaque. 

Infusible;    blackens     and    becomes 
magnetic;  effervesces  in  hot  acid. 

3- 

Brittle. 

3-8 

Compact, 
fibrous  and 
botryoidal. 

None. 

Opaque. 

Water  in    closed   tube;   black    and 
magnetic  on  charcoal. 

\ 

4-5 

Brittle. 

5-5 

III.  Also        Basal,             Usually 
massive.           perfect.           opaque. 

Infusible;    zinc   coating    with  soda 
on  charcoal;   soluble  in  acid. 

4- 


4-5 


5-25 


5-25 


Brittle. 

4- 

I.  Usually 
massive. 

Doclecahe- 
dral,  perfect. 

Translucent 
to  opaque. 

. 

Reactions  for  sulphur;  zinc  coating 
with  soda  on  charcoal. 

Brittle. 

3-8 

III.  Also 
compact. 

Rhombohe- 
dral,  perfect. 

Translucent 
to  opaque. 

Infusible;     blackens    and   becomes 
magnetic;   efferveses  in  hot  acid. 

i  Brittle. 

4- 

Compact, 
botryoidal, 
fibrous,   etc. 

Uneven, 

splintery, 
etc. 

Opaque. 

Water    in    closed    tube;     magnetic 
on  charcoal. 

IV.  Usually 

. 

Brittle. 

4.2 

massive,  fi- 
brous or 
botryoidal. 

Prismatic, 
perfect. 

Opaque. 

Like  limonite. 

56 


B.     MINERALS  WITH 


Analytical    Key. 

Species. 

Composition 

Lustre. 

Color. 

Streak. 

II.  Streak  Yellow. 
—  Continued. 

I 

Compact. 

Quartz  (Jasper) 

(33). 

Si02 
+Fe203 

Nearly  dull. 

Brown  to 
yellow. 

Light 
yellow. 

Crystalline. 

Quartz  (Ferrugi- 
nousQuartz)  (33). 

SiO2 
+Fe203. 

Vitreous  to 
nearly  dull. 

Brown  to 
yellow. 

Light 
yellow. 

Asp  haltum  (84)  . 

C,H,O,etc. 

Resinous  to 
dull. 

Brownish 
black  to 
black. 

Dark  brown. 

1 

G.  under  2.5 

Mineral  Coal 

(84). 

C,H,O,etc. 

Resinous  to 
submetallic. 

Brown  to 
black. 

Brown 
to  black. 

i 
1 

\ 

i 

Kaolinite  (car- 
bonaceous) (78). 

Al2Si2O7 
+2H20. 

Dull. 

Black. 

Black. 

G.  3-8 

Wad  (32). 

MnOa 

-fH20. 

Dull. 

Black. 

Black. 

! 

G.  under  2. 

Mineral  Coal 

(84). 

•     . 
C,H,O,  etc. 

Resinous  to 
submetallic. 

Brown  to 
black. 

Brown  to 
black. 

G.  nearly  4. 

Wad  (32). 

MnOa 

-       +H20 

Dull. 

Black. 

Black. 

G.  over  6. 

Melaconite  (22). 

CuO. 

Metallic  to 
dull. 

Black. 

Black. 

• 

Psilomelane 

(32). 

1  +H20. 

Submetallic. 

Black. 

Brownish 
black. 

G.  under  6. 

Menaccanite 

(25). 

(FeTi)203. 

Submetallic. 

Black. 

Brownish 

black. 

1 

Samarskite  (35). 

Complex 
columbate. 

Submetallic, 
shining. 

Black. 

Reddish 
brown. 

G.   over    7  . 

Wolframite  (41). 

Compare  Columbite. 

(FeMn) 
WO4. 

Submetallic. 

Brownish 
black. 

Dark  brown 
to  black. 

1 
I 

Crystalline. 
G.  over  5. 

Columbite  (35). 

Compare  Psilome- 
lane, Menaccanite 
ana  Samarskite. 

FeCb206. 

Submetallic. 

Black. 

Dark  red 
to   black. 

NON-METALLIC  LUSTRE. 


57 


H. 

Tenacity. 

G. 

Form. 

Cleavage. 

Properties. 

Confirmatory  Chemical   Tests. 

7- 

Brittle. 

2.6 

III.  Com- 
pact. 

^one. 

Translucent 
to  opaque. 

Infusible  and  insoluble. 

7- 

Brittle. 

2.6 

III.  Often 
massive. 

None. 

Translucent 
to  opaque. 

Infusible  and  insoluble. 

i-5 

Brittle  to 
flexible 

i-3 

Amorphous. 

Conchoidal. 

Opaque. 

Fuses  and  burns  with  flame. 

2. 

Brittle. 

i-5 

Amorp  h  ous 
often  lami- 

Even or 
conchoidal. 

Opaque. 

Infusible;   burns. 

nated. 

I. 

Plastic  to 
earthy 

2-5 

IV.  Usually 
compact  or 
earthy. 

Earthy. 

Opaque. 

Infusible;   water  in  tube. 

I. 

Earthy  . 

3-8 

Amorphous. 

IV.   Earthy. 

Opaque. 

Water  in  closed  tube;   amethystine 
bead  with  borax;    evolves     chlo- 

rine with  HC1. 

2-5 

Brittle. 

i-5 

Amorphous, 
often  lami- 

Even or 
conchoidal. 

Opaque. 

Infusible;  burns. 

nated. 

3- 

Brittle  to 
earthy 

3-8 

Amorphous. 

Uneven  to 
earthy. 

Opaque. 

Water  in  closed   tube;  amethystine 
bead    with  borax;   evolves    chlo- 
rine with  HC1. 

3- 

Brittle  to 
earthy 

6.25 

IV.  Usually 
massive    or 
earthy. 

Uneven  or 
earthy. 

Opaque. 

Infusible;  copper  with  soda  on  char- 
coal;   green   solution  with   nitric 
acid. 

5- 

Brittle. 

4-2 

Compact  or 
botryoidal. 

Even  or 
conchoidal. 

Opaque. 

Infusible;    water    in    closed    tube; 
evolves  chlorine  with  HC1. 

5-5 

Brittle. 

4-75 

III.  Often 
laminated 

None. 

Opaque. 
Often  slight- 

Infusible;  reactions  for  iron. 

ly  magnetic. 

5-5 

Brittle. 

5-7 

IV.  Also 
massive. 

Uneven  or 
conchoidal. 

Opaque. 

Emerald-green     bead     with    SPh; 
green  bead  with  soda. 

5-25 

Brittle. 

7-4 

V.  Also  lam- 
ellar or 
massive. 

Prismatic, 
perfect. 

Opaque. 

Fuses  easily  to  a  magnetic  globule; 
reactions  for  manganese. 

6. 

Brittle. 

6. 

IV.  Usually 
in  crystals. 

Prismatic. 

Opaque. 

Infusible. 

B.     MINERALS     WITH 


Analytical  Key. 

Species. 

Composition. 

Lustre. 

Color.               Streak. 

Glauconite  (76). 

(AlFeK)Si 
O3-f-H2O. 

Dull. 

Dark  green. 

Lighter 
green. 

i 

Streak 
green. 

Prochlorite  (81). 

(AlMgFe)3 
SiO5-f-H2O. 

Pearly  to 
dull. 

Dark  green. 

Lighter 
green. 

L. 

s 

Ripidolite  (81). 

Al2Mg5Si3 
014+4H20. 

Pearly. 

Deep  green. 

Greenish. 

Streak   blue. 

Vivianite  (37). 

Fe3P208 
+8H2O. 

Vitreous  to 
pearly  or 
dull. 

Blue  to 
green. 

Bluish. 

Streak 

Atacamite   (17). 

CuCl 
+3H2Cu02. 

Adamantine 
to  vitreous. 

Green.    - 

Apple- 
green. 

green. 

Xot  mica- 

ceous. 

Malachite   (46). 

Compare 

Cu»GO4 
+H20. 

Adamantine, 
silky  or  dull. 

Green. 

Paler  green. 

. 

Ch  rysocolla  . 

a 

as 

^     |  Streak 
green. 
^      j  Micaceous. 

Lepidomelane 

(56). 

(AlFeK)2 
SiO4. 

Adamantine 
to   pearly. 

Black. 

Grayish 
green. 

c 

Compare  Riptdolite. 

g 

£ 

Azurite  (46). 

5  +H20. 

Vitreous  to 
dull. 

Blue. 

Paler  blue. 

|jy 

g 

Streak   blue. 

i 

Chrysocolla 

GuSiO3 
+2H2O. 

Vitreous  to 
dull. 

Bluish 
green. 

Bluish. 

(68). 

Malachite    (46). 

Cu2C04 
+H2Q. 

Adamantine, 
silky  or  dull. 

Green. 

Paler  green. 

Streak 
greenish. 

Pyroxene 

(Augite)    (47). 

(GaMgAl 
Fe)Si03. 

Vitreous. 

Greenish 
black. 

Grayish 
green. 

1 

Amphibole  (49) 

(Hornblende). 

(GaMgAl 
Fe)Si03. 

Vitreous. 

Greenish 
black. 

G  ravish 
green. 

" 

Azurite  (46). 

Cu3C2O7 
-fH20. 

Vitreous  to 
dull. 

Blue. 

Paler  blue. 

Streak  blue. 

Lapis-Lazuli 

(CaNaAl)2 
SiO4. 

Vitreous 

Blue. 

Blue. 

(57)- 

«!| 

Streak  blu- 
ish or 
greenish. 

Turquois  (38). 

Compare  Lapis- 

A12P208 
+5H20. 

Waxy. 

Blue. 

Bluish  to 
greenish 
white. 

Lazuli,  Pyroxene 

and  Amphibole. 

| 

NON-METALLIC     LUSTRE. 


59 


H.        Tenacity. 

G. 

Form. 

Cleavage. 

Properties.           Confirmatory  Chemical  Tests. 

I. 

Granular 
and  earthy. 

2-3 

Amorphous. 

Earthy. 

Opaque. 

Water  in  closed  tube. 

1-5 

Somewhat 
sectile. 

2.8 

III.  Usually 
finely 
foliated. 

Basal, 
perfect. 

Translucent 
to  opaque. 

Fuses    \vith    difficulty;      water     in 
closed  tube. 

2.25 

Flexible 
and  sectile. 

2.7 

V.  Foliated 
or 
micaceous. 

Basal, 
perfect. 

Emerald- 
green  by 
trans,  light. 

Like  prochlorite. 

2. 

Sectile  to 
earthy. 

2.6 

V.  Often 
massive  or 
earthy. 

Clinopina- 
coidal, 
perfect. 

Translucent 
to  opaque. 

Fuses  easily  to   magnetic   globule; 
water  in   closed  tube;  soluble   in 
acid. 

3-25 

Brittle. 

3-75 

IV.  Also 
massive. 

Brachy- 
pinacoidal, 
perfect. 

Transparent 
to  opaque. 

Fuses    with   a   blue   flame;    yields 
metallic  copper  •    water  in  closed 
tube. 

V.  Often 

3-75 

Brittle. 

3-9 

botryoidal, 
fibrous  or 

Basal, 
perfect. 

Translucent 
to  opaque. 

Fuses  and  yields  copper;   water  in 
closed  tube;  effervesces  with  acid. 

i 

earthy. 

Sectile  to 

III.  Foliated 

Basal, 

Translucent   Fuses  to  a  magnetic    globule;    de- 

• 

brittle. 

3- 

micaceous. 

perfect. 

to  opaque. 

composed  by  HC1. 

4- 

Brittle. 

3-7 

V.  Also 
massive. 

Clinodome, 
perfect. 

Translucent 
to  opaque. 

Like  malachite. 

3. 

Brittle  to 
sectile. 

2.2 

Amorphous 
or  botrvoi- 
d*l. 

Conchoidal 
or  uneven. 

Translucent 
to  opaque. 

Infusible;     water    in    closed  tube; 
copper  on  charcoal;   decomposed 
by  HC1. 

' 

1 

V.  Often 

3-75 

Brittle.           3.9 

botryoidal, 
fibrous  or 

Basal, 
perfect. 

Translucent 
to  opaque. 

Fuses  and  yields  copper;   water  in 
closed  tube;  effervesces  with  acid. 

earthy. 

5-5 

Brittle. 

34 

V.  Massive 
or  fibrous. 

Prismatic, 
perfect. 

Translucent 
to  opaque. 

Fusible;  insoluble. 

5-5 

Brittle. 

3-2 

V.  Massive 
or  fibrous. 

Prismatic, 
perfect. 

Translucent 
to  opaque. 

Like  pyroxene. 

4.        Brittle. 

3-7 

V.  Also 
massive. 

Clinodome, 
perfect. 

Translucent 
to  opaque. 

Fuses  and  yields  copper;   water  in 
closed  tube;  effervesces  with  acid. 

5.5     Brittle. 

2.4 

I.  Usually 
compact. 

None. 

Opaque. 

Fusible;   gelatinizes  with  HC1. 

6. 

Brittle. 

2.7 

Amorphous. 

None. 

Opaque. 

Infusible;     water    in   closed   tube; 
soluble  in  acid. 

B.     MINERALS  WITH 


Analytical    Key. 

Species. 

Composition. 

Lustre. 

Color. 

Streak. 

5s» 

i 

^5 

* 

V 

i4i 

1 
K 

i 

g5 
1 

N 

G.  s-5 
Waxy. 

Cerargyrite(i6). 

AgCl. 

Resinous  to 
dull. 

Gray. 

Gray, 
shining. 

G.  i. 
Like  resin. 

Amber  and 
Copal  (84). 

C,H,0,  etc. 

Resinous. 

Yellow  and 
brown  to 
white. 

White. 

Micaceous. 
Folise  highly 
elastic. 

Muscovite  (56). 

Compare 
Hydromica  . 

AlKSiO4. 

Pearly. 

White, 
brown, 
green,  etc. 

White. 

Micaceous. 
Folise  some- 
what elastic. 

Ripidolite   (81). 

Compare 
Prochlorite. 

Mg5Al2Si3 
014+4H20. 

Pearly. 

Deep  green. 

White. 

Greasy  feel. 
Foliated  or 
compact. 

Talc  (75). 

Pyrophyllite 

(75)- 

Compare  Gypsum. 

MgSiO 
+H20. 

Al2Si3O9 
-f-H2O. 

Pearly  to 
dull. 

Dull  to 
pearly. 

Green  to 
gray,  etc. 

White,  gray, 
green,  etc. 

White. 
White. 

Compact. 
Bloats  on 
water  when 
dry. 

Sepiolite  (76). 

Mg2Si308 
+2H2O. 

Dull. 

White 
to  gray 

White. 

Compact, 
earthy  or 
clayey. 

Kaolinite 

(Clay)    (78). 

Calcite    (Chalk) 
(44). 

Opal  (Tripolite 
and  Siliceous 
Tufa)   (34). 

Al2Si2O7 
+  2H20. 

CaCO3. 

SiO2. 
+H20. 

Dull  to 
pearly. 

Dull. 
Dull. 

White,  gray, 
yellow,  red, 
blue,    green, 
etc. 

White. 

White  to 
gray. 

Like  color. 

White. 

White  to 
gray. 

Blue  or 
green. 

Prochlorite(Si). 

(AlMgFe)3 
SiO5+H2O. 

Pearly  to 
dull 

Dark  green. 

Gray. 

Soluble  in 
water, 
having  taste. 

Sassolite  (39). 
Borax  (40). 

Compare  Halite. 

H6B206. 

Na2B4O7 
+ioH2O. 

Pearly. 

Vitreous  to 
resinous 

White. 
White. 

White. 
White. 

Very  light, 
hbrous 
nodules. 

Ulexite  (40). 

NaCaB2O9 
+5H20. 

Silky  to 
dull 

White. 

White. 

Yields  much 
water  in 
closed   tube. 

Gypsum  (43). 

CaSO4 
+2H2O. 

Pearly  to 
silky  and 
dull 

White,  gray 
brown,  etc 

White. 

NON-METALLIC  LUSTRE. 


61 


Other 
H.    !     Tenacity.        G.           Form.            Cleavage.    |  Properties. 

Confirmatory  Chemical  Tests. 

1-5 

2.25 

Waxy  and    | 

sectile.l 

i 
5-5 

I.  Usually 
compact. 

S^one. 

Transparent 
to  opaque. 

H"uses;    silver    on    charcoal;    reacts 
for  chlorine  with  CuO  and    SPh. 

i 
Brittle. 

I  .       Amorphous. 

^fone. 

Transparent 
to 
translucent. 

^uses    readily   and    burns   with    a 
yellow  flame. 

2. 

Sectile  and 
elastic. 

V.  Usually 
2.8      foliated   or 
lamellar. 

Basal, 
perfect. 

Transparent, 
to 
translucent. 

[nfusible  and  insoluble. 

2. 

Flexible 
and  sectile. 

2.7 

V.  Foliated 
or  mica- 
ceous. 

Basal, 
perfect. 

Emerald- 
green  by 
trans,  light. 

Fuses     with     difficulty;      water    in 
closed  tube. 

I. 

i-5 

Sectile  and 
inelastic. 

Somewhat 
sectile. 

2.6 

2.8 

IV.  Usually 
foliated, 
sometimes 
compact 
TV.  Usually 
compact, 
sometimes 
foliated. 

Basal, 
perfect 

Basal, 
perfect. 

Greasy   feel. 
Translucent. 

Greasy   feel. 
Translucent 
to  opaque. 

[nfusible  and  insoluble;  little  water 
in  closed  tube. 

Fuses  with  difficulty;  yields  water; 
blue  color  with    cobalt    solution. 

2.25 

Somewhat 
sectile. 

Very 
light. 

Compact. 

None. 

Opaque. 

Infusible;   water    in    closed    tube; 
pink  color    with    cobalt  solution; 
gelatinizes  with  HC1. 

«-S 

i. 
i. 

Plastic  or 
earthy. 

Earthy. 
Earthy. 

2-5 

2.6 

1-7 

2.8 

IV.  Usually 
compact  or 
clayey. 

III.  Com- 
pact. 

Amorphous. 

Basal, 
perfect. 
Finely  scaly. 

Earthy. 
Earthy. 

Translucent 
to  opaque. 

Opaque. 
Opaque. 

Infusible  and   insoluble;    water   in 
closed  tube;  blue  color  with  cobalt 
solution. 

Infusible;     soluble     with     efferves- 
cence;  alkaline  reaction    after 
heating. 

Infusible;   water  in  tube. 

!-5 

Somewhat 
sectile. 

III.    Usually 
finely  foli- 
ated. 

Basal, 
perfect. 

Transluceut 
to  opaque. 

Fuses  with  difficulty  ;  water  in  closed 
tube. 

2.25 

Brittle. 
Brittle. 

2.4 
2.3 

VI.   Scaly. 

V.  Usually 
crystalized. 

Basal, 
perfect. 

Perfect. 

Translucent. 
Taste 
acidulous. 

Translucent 
to  opaque. 
Taste 
alkaline. 

Fuses  to  4  a    clear    glass,    coloring 
flame    green;     soluble   in  water; 
water  in  closed  tube. 

Puffs  up  and  fuses  to    clear    glass, 
coloring  flame  yellow;   soluble  in 
water;   water  in  closed  tube. 

<• 

Sectile. 

1.65 

Nodules. 

Finely 
fibrous. 

Opaque. 

Fuses  readily  to  a  clear  glass,  col- 
oring flame  yellow;   with  HaSO4 
the  flame  is  green. 

2. 

Sectile  to 
brittle. 

2-3 

V.  Usually 
foliated, 
massive  or 
fibrous. 

Clinopina- 
coidal, 
perfect. 

Transparent 
to  opaque. 

Fuses;   water  in  closed  tnbe;    sul- 
phur reaction  with  soda  on  char- 
coal. 

62 


B.     MINERALS  WITH 


Analytical    Key. 

Species.             Composition. 

Lustre. 

Color. 

Streak. 

j 

Green  to 

Pyromorphite 

(36). 

-fPbdg. 

Resinous. 

yellow  and 
brown. 

White. 

Green, 

Mimetite  (36).' 

3Pb3As2O8 
+PbCl2. 

Resinous. 

Pale  yellow 
to  brown. 

White. 

yellow  or 

brown. 

Vanadinite  (36). 

+PbCl2. 

Resinous. 

Yellow  to 
brown. 

Yellowish 
white. 

<6 

i  Yellow  to 

| 

Wulfenite  (41). 

PbMoO4.       |  Resinous.       !  green  and 

White. 

1 

brown. 

^ 

Anglesite  (42). 


PbSO4. 

Adamantine 
to  vitrebus. 

White. 

White. 

White. 

1 

Cerussite   (45). 

PbC03. 

Adamantine 
to  vitreous. 

White  to 
gray. 

White. 

_ss 

1 

1' 

Rhodochrosite    :MnCO3.          Vitreous. 

Rose-red 
to  brown. 

White. 

(44)- 

fe 

^X 

e 

• 

L. 

•o 

I 

o 

Siderite   (44). 

FeC03. 

Vitreous. 

Gray  to 
brown. 

White  to 
gray. 

• 

is 

•<Si 

cq 

. 

Grayish, 

1 

Red,  brown 
or  gray. 

Smithsonite 

(44)- 

ZnCO3. 

Vitreous  to 
dull. 

greenish 
or   brownish 
white. 

White  to 
gray. 

1 

Sphalerite   (7). 

ZnS. 

Resinous. 

Pale  yellow 
to  brown. 

\Vhite  to 
gray. 

r^ 

1) 

Calamine   (69). 

Zn2SiO4 
+H20. 

Vitreous  to 
dull. 

Gray, 
yellow  to 
brown. 

White  to 
gray. 

^ 

White  to 

Barite  (42). 

BaSO4. 

Vitreous. 

bluish  or 

White. 

brownish. 

White  or 

Celestite  (42). 

SrS04. 

Vitreous. 

White  to 
bluish. 

White. 

bluish  or 

greenish. 

Witherite   (45). 

BaCO3. 

Vitreous. 

White 

White. 

Strontianite 

(45)- 

SrCO3. 

Vitreous. 

White  to 
greenish. 

White. 

Compare 

Smithsonite. 

NON-METALLIC    LUSTRE. 


H.       Tenacity. 

G. 

Form. 

Cleavage. 

Other 
Properties. 

Confirmatory  Chemical  Tests. 

3-75 

Brittle. 

6.8 

III.  Often 
botryoidal 
or  massive. 

'races. 

Translucent. 

Readily  fusible;  lead  with  soda  on 
charcoal;  chlorine  with  CuO 
andSPh;  white  sublimate  in  tube. 

3-5 

Brittle. 

7.2 

III.  Also 
massive. 

mperfect. 

Translucent. 

Like  pyromorphite,  but  gives  ar- 
senical odor  on  charcoal. 

3- 

Brittle. 

7- 

III.   Usually 
in    incrusta- 
tions. 

None. 

Opaque. 

Like  pyromorphite. 

3- 

Brittle. 

6.7 

II.  Very  thin, 

square,    tab- 
ular crystals. 

Octahedral. 

Translucent. 

Fuses  readily;  lead  on  charcoal 
with  soda. 

3- 

Brittle. 

6.25 

IV.  Aso 

massive  and 
stalactitic. 

3rismatic, 
interrupted. 

Transparent 
to  opaque. 

Fuses  readily;  lead  with  soda  on 
charcoal;  coin  test  for  sulphur. 

3-5 

Brittle. 

6.5 

IV.  Also 
massive  and 
stalactitic. 

Msrnatic, 
imperfect. 

Transparent 
to  opaque. 

Fuses  readily;  lead  with  soda  on 
charcoal;  effervesces  with  acid. 

4- 

Brittle. 

3-6 

III.  Also 
massive  and 
botryoidal. 

^hombohe- 
dral, 
perfect. 

Translucent. 

Infusible;  amethystine  bead  with 
borax;  effervesces  with  acid. 

4- 

Brittle. 

3-8 

III.  Also 
compact  and 
concre- 
tionary. 

•Ihombohe- 
dral, 
perfect. 

Translucent 
to  opaque. 

Infusible;  blackens  and  becomes 
magnetic;  effervesces  with  acid. 

2  to 

4- 

Brittle  to 
friable. 

4- 

III.  Com- 
pact to 
earthy. 

None. 

Opaque. 

Infusible;  effervesces  with  acid; 
zinc  coating  on  charcoal. 

3-5 

Brittle. 

4- 

I.  Also 
massive. 

Dodecahe- 
dral,  perfect. 

Translucent 
to  opaque. 

Infusible;   zinc    coating  with    soda 
on  charcoal;   evolves  H2S  with 
HC1. 

2  to 

4- 

Brittle  to 
friable. 

3-5 

IV.  Compact 
to  earthy 

None. 

Opaque. 

Infusible;  yields  water;  green  color 
with  cobalt  solution;  gelatin- 
izes with  HC1. 

3- 

Brittle. 

4-5 

IV.  Also 
massive    anc 
stalactitic 

Basal  and 
prismatic, 
perfect. 

Transparent 
to  opaque. 

Fusible;  colors  flame  yellowish 
green;  sulphur  reaction  with 
soda  on  silver. 

3-25 

Brittle. 

4- 

IV.  Also 
massive,  fi 
brous,    glob 
ular,  etc 

Basal  and 
prismatic, 
perfect. 

Transparent 
to  opaque 

Like  barite;   but  colors  flame    red. 

3-5 

Brittle. 

4-3 

IV.  Also 
globular, 
etc 

Prismatic, 
distinct 

Translucent 
to  opaque. 

Fusible;  colors  flame  yellowish 
green;  effervesces  with  acid. 

3-75 

Brittle. 

3-7 

IV.  Also 
globular, 
etc 

Prismatic, 
perfect 

Transparent 
to  opaque 

Infusible;    colors  flame  red;   effer- 
vesces with  acid. 

OP 


UITI7ERSITT 


64 


B.     MINERALS     WITH 


Analytical  Key. 

Species. 

Composition. 

Lustre. 

Color.               Streak. 

Black  to 

elastic. 

Biotite  (56). 

^K2MgFe 
Al)2SiO4. 

Pearly, 
splendent. 

deep  green 
and  brown. 

White. 

Black,  even 

in  thin 
folise. 

Lepidomelane 

(56). 

(K2FeAl)2 
SiO4. 

Adamantine 
to  pearly. 

Black. 

Grayish 
green. 

. 

Foliae 

somewhat 
elastic. 

Ripidolite  (81). 

Al2Mg5Si3 
014+4H20. 

Dearly. 

Deep  green.  Greenish. 

Deep  green. 

ricaceous 

Phlogopite(56). 

(K2MgAl)2 
Sio4. 

Pearly  to 
submetallic. 

Yellowish 
brown. 

White. 

^ 

Folise 

Muscovite  (56). 

(K2A1)2 
SiO4. 

Pearly. 

White, 
brown,  pale 
green,  etc. 

White. 

elastic. 
>?ot  belong- 

^ 

ing  to  the 
foregoing. 

Lepidolite   (56). 

(Li2K2Al)2 
SiO4 

Pearly. 

Rose-red 
and  violet  to 

White. 

S 

white. 

1 
\ 

| 

Hydromica(So)  . 

(K2A1)2 
SiO4) 
+H20. 

Pearly. 

White  to 
greenish. 

White. 

f&* 

£ 

'^ 

. 

*- 

"s 

c 

Foli^       e  Margarite  (82). 

(CaFeAl)3 

Pearly. 

Reddish 
white  to 

White. 

o 

\ 

1 

5        * 

gray. 

«> 

£ 

>< 

f 

yj 

White,  and 

i 

Calcite  (44). 

CaCO3. 

Vitreous 
to  dull. 

all  colors 
when 

White  to 
gray. 

1 

Dilute  HC1. 

impure. 

S 

1 
e 

Aragonite    (45). 

CaC03. 

Vitreous 
to  dull. 

White  to 
gray,  etc. 

White. 

I 

1 

Dolomite   (44). 

(CaMg) 
C03. 

Vitreous 
to  dull. 

White  to 
gray,  etc. 

White. 

Strong  HC1. 

Magnesite  (44). 

MgC03. 

Vitreous 
to  dull. 

White  to        ,,„. 
gray,  etc.l^te. 

White  to 

Saline  taste. 

Halite   (16).         JNaCl. 

Vitreous. 

gray,  brown, 

White. 

etc. 

Wavellite  (38). 

Al3P4Oi9 
+i2H2O 

Vitreous. 

White  to 
green, 
brown,   etc. 

White. 

Acicular 

or  fibrous. 

Serpentine 

(Chrysotile)  (77) 

Mg2Si04. 
-r-H20 

Silky. 

Green  to 
yellow  . 

White. 

Compare   Asbestus. 

NON-METALLIC  LUSTRE. 


H. 

Tenacity. 

G. 

2.9 

Form. 

Cleavage. 

Other 
Properties. 

Confirmatory  Chemical  Tests. 

2-75 

Elastic  and 
sectile. 

III.  Tabular 
or  foliated. 

Basal,  very 
perfect. 

Transparent 
to  opaque. 

Fuses  with  difficulty;  deocmposed 
by  H2SC>4;  reactions  for  iron. 

3- 

Sectile  to 
brittle. 

3- 

III.  Tabular 
or  foliated. 

Basal, 
perfect. 

Translucent 
to  opaque. 

Fuses  to  magnetic  globule;  decom- 
posed by  HC1. 

2-5 

2-75 

Flexible  and 
sectile. 

2.7 

V.  Tabular 
or  foliated. 

Basal, 
perfect. 

Transparent. 
Emerald- 
green  by 
trans,  light. 

Fuses  with  difficulty;  much  water 
in  closed  tube. 

Elastic  and 
sectile. 

2.8 

IV.  Tabular 
or  foliated. 

Basal,  very 
perfect. 

Transparent 
to 
translucent. 

Fuses  with  difficulty;  decomposed 
by  H2S04. 

2-5 

Elastic  and 
sectile. 

2.8 

V.  Tabular 
or  foliated. 

Basal,  very 
perfect. 

Transparent 
to 
translucent. 

Infusible  and  insoluble;  water  in 
closed  tube. 

3- 

Elastic  and 
sectile. 

2.9 

IV.  Tabular 
or  foliated. 

Basal,  very 
perfect. 

Translucent. 

Fuses  with  intumescence,  coloring 
the  flame  purplish  red. 

2-5 
4- 

Elastic  and 
sectile 

2.75 

Tabular  or 
foliated. 

Basal, 
perfect 

Translucent. 
Greasy   feel. 

Infusible;   water  in  closed  tube. 

Laminae  stiff 
and  brittle. 

3- 

IV.  Usually 
lamellar  or 
foliated. 

Basal, 

perfect. 

Translucent. 

Infusible;  whitens;  water  in  closed 
tube. 

3- 

Brittle. 

2.7 

III.    Rhom- 
bohedrons, 
also  massive, 
compact,  etc. 

Rhombohe- 
dral,  perfect. 

Strong 
double  re- 
fraction. 

Infusible;  glows;  alkaline  reaction 
after  heating;  effervesces  in  cold 
dilute  acid. 

3-75 

Brittle. 

2.9 

IV.  Prismat- 
ic, also  sta- 
lactitic,  etc. 

Prismatic, 
imperfect. 

Transparent 
to 
translucent. 

Like  calcite,  but  whitens  and  falls 
to  pieces. 

3-5 

Brittle. 

2.85 

III.    Rhom- 
bohedrons, 
also  massive 
and  compact. 

Rhombohe- 
dral,  im- 
perfect. 

Translucent 
to  opaque. 

Infusible;     alkaline    reaction    after 
heating;   does  not  effervesce 
freely  in  cold,  dilute  HC1. 

3-5 

Brittle. 

3- 

III.  Usually 
compact. 

Rhombohe- 
dral,  perfect. 

Transparent 
to  opaque. 

Like  dolomite. 

2-5 
3-75 

Brittle. 

2.2 

I.  Cubes, 
also  massive. 

Cubic, 
perfect. 

Transparent 
to 
translucent. 
Saline  taste. 

Fuses,  coloring  flame  deep  yellow; 
soluble  in  water. 

Brittle. 

2-3 

IV.    Usually 
in  radiate, 
globular 
masses. 

Prismatic, 
perfect  to 
fibrous. 

Translucent. 

Swells  up,  colors  flame  green,  but 
is  infusible;  blue  color  with  co- 
balt solution;  much  water  in 
tube. 

3- 

Flexible  and 
sectile. 

2.2 

Fibrous 
veins. 

Delicately 
fibrous. 

Translucent. 

[nfusible;   water  in  closed  tube. 

66 


B.     MINERALS    WITH 


Analytical  Key. 

Species. 

Composition. 

Lustre. 

Color. 

Streak. 

Octahedral 

White, 

cleavage. 
Cubic 

Fluorite  (18). 

CaF2. 

Vitreous. 

green,  violet  ,™  . 
to  blue,  yel- 

crystals. 

low,    etc. 

i 

Brucite  (31). 

MgO 
+H20. 

Pearly. 

White  to 
greenish. 

White. 

8 

"u 

0 

Only  one 
perfect 
cleavage, 
tabular  or 

Stilbite  (74). 

(CaNa2)Al2 
Si6Oi6 
+6H20. 

Pearly. 

White  to 
yellow  and 
red. 

White. 

V 

foliated. 

(CaNa2)Al2 

White  to 

i. 

Heulandite(74). 

Si6016 
+5H20. 

Pearly. 

red,  gray 
and  brown. 

White. 

u 

"o 

B 

Cryolite  (19). 

Na6Al2F12. 

Vitreous. 

White  to 
brown. 

White. 

& 

Q} 
£ 

Not  belong- 
ing to  the 
foregoing. 

Laumontite 

(67)- 

1  +4H20. 

Vitreous. 

White  to 
red. 

While. 

6 

a 
i 

'•e 
s 

Anhydrite   (42). 

CaSO4. 

Vitreous  to 
pearly. 

White  to 
bluish  or 
reddish. 

White. 

^ 

si 

*Q 

| 

43 
sr 

CT) 

o 

a 

0  1 

•2  ' 

Yields  little 

Cryolite  (19). 

Na6Al2F12. 

Vitreous. 

'Xln.™^- 

. 

lO 

or  no  water 

( 

£ 

ti 

in  closed 
tube. 

Anhydrite  (42). 

CaSO4. 

Vitreous  to 
pearly. 

White  to 
bluish  or    i  White, 
reddish. 

J 

ts 

Bluish 
green. 

Chrysocolla 

(68). 

CuSiO3 
+2H20. 

Vitreous  to 
dull. 

Bluish  green  „„.,.  , 
to  blue.lWhltlsh- 

u 

1 

Gibbsite  (31). 

A12O3 
+3H20. 

Vitreous  to 
pearly  and 
dull. 

White  to 
grayjWhxte. 

2 

White. 

z 

Sepiolite   (76). 

Mg2Si308 
2H2O. 

Dull. 

White. 

White. 

u 

A 

.1 

Serpentine  (77). 

Mg3Si2O7 
+2H2O. 

Resinous, 
waxy, 

Green,  yel- 
low,  brown, 

White. 

greasy. 

etc. 

Yields  water 
in  closed 
tube. 

Dewylite   (77). 

H2Mg2S53O9 
+4H20. 

Resinous  to 
greasy. 

Yellow  to 
gray  and 
greenish. 

White. 

Finite  (79). 

K2Al4Si5O17 
+3H20. 

Waxy  to 
dull. 

Gray  to 
green. 

White. 

NON-METALLIC     LUSTRE. 


67 


H. 

4- 

Tenacity. 

G. 

Form. 

Cleavage. 

Other 
Properties. 

Confirmatory  Chemical  Tests. 

Brittle. 

3-2 

I.  Cubes, 
also  massive. 

Octahedral, 
perfect. 

Phosphores- 
cent when 
heated. 

Decrepitates,  fuses  and  gives  al- 
kaline reaction;  reaction  for 
fluorine  with  HKSOv 

2-5 

Flexible 
and  sectile. 

2.4 

III.   Usually 
foliated  or 
fibrous. 

Basal, 
perfect. 

Translucent. 

Infusible;    alkaline    after    heating; 
red  color  with  cobalt  solution; 
water  in  closed  tube;  soluble.    ' 

3-75 

Brittle. 

2.1 

IV.  Usually 
in  sheaf-like 
aggregates. 

Brachy- 
pinacoidal, 
perfect. 

Transparent 
to 
translucent. 

Fuses  with  intumescence;  yields 
water;  decomposed  by  HC1. 
without  gelatinizing. 

3-75 

2-5 

Brittle. 

2.2 

V.  Also 
globular  and 
massive. 

Clinopina- 
coidal, 
perfect. 

Transparent 
to 
translucent. 

Like  stilbite. 

Brittle. 

3- 

VI.  Usually 
massive. 

In  three 
directions. 

Translucent. 

Fuses  very  easily,  coloring  flame 
yellow;  fluorine  reaction. 

4- 

Brittle. 

2-3 

V.  Also 
columnar 
and  massive. 

Perfect. 

Opaque  and 
pulverulent 
on  exposure. 

Fuses  with  intumescence;  yields 
water;  gelatinizes  with  acid. 

3-25 

Brittle. 

2.9 

IV.  Also 
fibrous,  lam- 
ellar   and 
massive. 

Pinacoidal 
and  basal, 
perfect. 

Transparent 
to  opaque. 

Fusible;  alkaline  reaction;  sulphur 
reaction  with  soda  and  silver. 

2-5 

Brittle. 

3- 

VI.  Usually 
massive. 

Imperfect. 

Translucent. 

Fuses  very  easily,  coloring  flame 
yellow;  fluorine  reaction. 

3-25 

Brittle. 

2.9 

IV.  Often 
compact. 

None 
apparent. 

Translucent 
to  opaque. 

Fusible;  alkaline  reaction;  sulphur 
reaction  with  soda  and  silver. 

3. 

Brittle  to 
sectile. 

2.2 

Compact, 
sometimes 
botryoidal. 

None. 

Translucent 
to  opaque. 

Infusible;  colors  flame  green; 
yields  water;  copper  with  soda 
on  charcoal. 

3- 

Tough. 

2.4 

V.  Usually 
stalactitic  or 
incrusting. 

Basal, 
perfect. 

Translucent. 
Argillaceous 
odor. 

lufusible;  yields  water;  blue  color 
with  cobalt  solution.' 

2-5 

Somewhat 
sectile. 

Very 

light. 

Compact. 

None. 

Opaque. 
Absorbs 
water. 

[nfusible;  water  in  closed  tube; 
pink  color  with  cobalt  solution; 
gelatinizes  with  HC1. 

3-5 

Brittle. 

2.6 

Compact  or 
finely  granu- 
lar. 

None. 

Translucent. 
Smooth  feel. 

Infusible;   yields  water. 

2-5 

Brittle. 

2.2 

Compact. 

None. 

Translucent. 

Infusible;   yields  water. 

3- 

Brittle. 

2-7 

Compact. 

None. 

Translucent 
to  opaque. 

Fusible;   yields  water. 

68 


B.     MINERALS  WITH 


Analytical    Key. 

Species. 

Composition.        Lustre. 

Color.               Streak. 

; 

Small  square 
crystals. 

Brookite   (27). 

Ti02. 

Adamantine. 

Brown  to 
yellowish 
and  reddish. 

White  to 
gray. 

5 

OJ 

Gelatinizes 

Willemite  ($i). 

Zn2SiO4. 

Vitreous  to 
resinous, 

Yellowish, 
greenish  and 

White. 

i 

Compare    Calamine. 

weak. 

brownish.! 

o 

! 

•i 

Effervesces 

White  to 

Cb 

0 

with  hot 
acid   (CO2). 

Smithsonite 
(44). 

ZnCO3. 

Vitreous  to 
dull. 

grayish,      „„. 
greenish  or   V 
brownish. 

"So 
P 

Effervesces 
with  hot 
acid   (H2S). 

Sphalerite  (7). 
Compare  Allanite. 

ZnS. 

Resinous. 

Pale  yellow 
to  brown. 

White  to 
gray. 

Enstatite    (47). 

MgSi03. 

Vitreous  to 
pearly. 

Grayish  and 
greenish  to 
brown. 

White  to 
gray. 

1 

rt 

3 
2 

Cleavage 
prismatic 
and  nearly 
rectangular. 

Hypersthene 

(47)- 

(MgFe) 
SiO3. 

Pearly  to 
metalloidal. 

Dark  brown- 
ish green 
to  black. 

Gray. 

i 

i 

G 

o 

Pyroxene 

(Augite)   (47). 

(CaMgAl 
Fe)Si03. 

Vitreous. 

Dark  green  Greenish 
to  black.                Sray* 

v 

*s 

c3 

\ 

fc 

1 

'a 

lAmphibole            (CaMgAl 
Cleavage           (Hornblende)     {        Fe)SiO3 

Vitreous. 

Dark  green  'Greenish 
to  black.               gray. 

•to 

• 

prismatic 

(49)- 

j| 

& 

and  distinct- 

\ 

„ 

1 

1 

ly  oblique. 

Titanite   (6$). 

L 

CaTiSiO5. 

Adamantine  Dark  brown  !  White  to 
to  resinous.;       to  black.               gray. 

^ 

0 

f' 

1 

8 

Cleavage 
basal, 
perfect. 

Chloritoid    (82). 

(AlFeMg)4 
Si06-j-H20. 

Pearly. 

Dark  gray     'G       ish  to 
and    green-        i-eenisn 
ish  to  black. 

^ 

> 

No  distinct 
cleavage. 

Allanite  ($$) 

Complex 
silicate. 

Submetallic 
to  resinous. 

Pitch-brown 
to  black. 

Gray. 

Lazulite  (38). 

MgAlP2Oo 
+H20. 

Vitreous. 

Blue. 

White. 

Blue. 

Sodalite  (57). 

O8-f2NaCl. 

Vitreous  to 
greasy. 

Blue,  etc. 

White. 

Red  to  brown. 
Weathers  black. 

Rhodonite  (48).  MnSiO3. 

Vitreous. 

Red  and 
brown  to 

White. 

gray. 

Effervesces  with 
hot  acid. 

Magnesite  (44). 

Jompare  Cancrinite. 

MgC03. 

Vitreous   to 
dull. 

White  to 
gray,  etc. 

White. 

NON-METALLIC  LUSTRE. 


69 


H. 

Tenacity. 

G. 

Form. 

Cleavage. 

Other 
Properties. 

Translucent. 

Confirmatory  Chemical  Tests. 

5-5 
5-5 

Brittle. 

4.2 

IV.  Rarely 
massive. 

Imperfect. 

Infusible  and  insoluble. 

Brittle. 

4- 

4-25 

III.  Usually 
massive. 

Imperfect. 

Translucent. 

Fuses  with      difficulty;     gelatinizes 
with  HC1. 

5- 

Brittle. 

III.  Often 
botryoidal 
or  earthy. 

Rhombohe- 
dral,  perfect. 

Translucent 
to  opaque. 

Infusible;     effervesces    with    HC1; 
zinc  coating  with  soda   on   char- 
coal. 

4- 

Brittle. 

4- 

I.  Also 
massive. 

Dodecahe- 
dral,  perfect. 

Translucent 
to  opaque. 

Infusible;   zinc  coating    with    soda 
on  charcoal;    evolves    H2S  with 
HC1. 

5-5 

Brittle. 

3-2 

IV.  Also 
massive  and 
lamellar. 

Prismatic, 
distinct. 

Translucent 
to  opaque. 

Infusible  and  insoluble. 

5-5 

Brittle. 

3-4 

IV.  Also 
massive  and 
lamellar. 

Prismatic, 
distinct. 

Translucent 
to  opaque. 

Fusible  to  a  black   magnetic   mass 
on  charcoal. 

5- 
5- 

Brittle. 

3-4 

V.  Often 
massive   and 
granular. 

Prismatic, 
perfect. 

Translucent 
to  opaque. 

Fusible;    insoluble. 

Brittle. 

3-2 

V.  Often 
blade  d  or 
massive. 

Prismatic, 
perfect. 

Translucent 
to  opaque. 

Fusible;   insoluble. 

5- 

Brittle. 

3-5 

V.  Squarish, 
wedge-shap- 
ed crystals. 

Prismatic, 
perfect. 

Translucent 
to  opaque. 

Fuses  with  intumescence. 

5-75 

Brittle. 

3-5 

V.  or  VI. 
Coarsely  foli- 
ated   or 
scaly. 

Basal, 
perfect. 

Translucent 
to  opaque. 

Infusible;   yields  water. 

5-75 
5- 

Brittle. 

3-6 

V.  Also 
massive   and 
granular. 

In  traces. 

Opaque. 

Fuses  with  intumescence  to  a  mag- 
netic mass. 

Brittle. 

3- 

V.  Octahe- 
drons,  also 
massive. 

Imperfect. 

Opaque. 

Whitens    and    yields    water;     blue 
color  is  restored  by  cobalt  solu- 
tion. 

5-5 

Brittle. 

2-3 

I.  Dodecahe- 
drons and 
massive. 

Dodecahe- 
dral,  distinct. 

Translucent. 

Fuses   with  intumescence;   gelatin- 
izes with  HC1. 

5-5 

Tough. 

3-5 

VI.  Com- 
pact or 
massive. 

Indistinct. 

Translucent 
to  opaque. 

Fusible;     amethystine     bead     with 
borax. 

4-5 

Brittle. 

3- 

III.  Usually 
compact. 

Rhombohe- 
dral,  perfect. 

Transparent 
to  opaque. 

Infusible;    alkaline    reaction    after 
heating;      does     not      effervesce 
freely  in  cold  dilute  acid. 

7° 


B.     MINERALS  WITH 


Analytical    Key. 

Species. 

CompositionJ       Lustre.               Color. 

Streak. 

rt 

Wollastonite 

CaSi03. 

Vitreous. 

White  to 
reddish. 

White. 

| 

(47^ 

'o 

o 

Pyroxene  (47). 

(CaMgFe) 
Si03. 

Vitreous. 

Green  to 
white. 

White. 

'O 

Little  or  no 

1 

water  in 

A 

closed    tube. 

Amphibole 

(Actinolite, 

(CaMgFe) 
Si03. 

Vitreous  to 

silky. 

Green. 

White. 

o  £ 

Asbestus)    (49)  . 

1| 

Amphibole 

(Tremolile, 
Asbestus)   (49). 

(CaMg) 
SiO3. 

Vitreous  to 
silky. 

White. 

White. 

Compare  Cyanite. 

is 

Pectolite  (67). 

Na,Ca4Si6 
Oi7+H20. 

Silky  to 
vitreous. 

White. 

White. 

u 

| 

Much  water 
in 
closed  tube. 

Thomsonite 

(70- 

2(CaNa2) 
Al2Si2O3 
+5H20. 

Vitreous  to 
pearly. 

White. 

White. 

1 

•8' 

| 

I 

Natrolite  (71). 

Na2Al2Si3 
010+2H20. 

Vitreous. 

White. 

White. 

9 

.s 

. 

tc 

"^ 

0 

p 
o 

1 

K 

c 

I 

\\ 

Little  or  no 

Amphibole  (49). 
(Jade  and  Neph- 
rite) . 

(CaMgFe) 

Vitreous. 

White  to 
green. 

White  to 
greenish. 

£ 

n 

rt   > 

water  in 

•IS 

C 

•*-•  ju 

closed  tube. 

1 

^ 

2 

O   w 

Wollastonite 

(47)- 

CaSiO3. 

Vitreous. 

White  to 
reddish. 

White. 

1 

sg 

^K 

•I?  fi 

>  c 

is 

h 

~  S 

o  \  —  ^ 

Much  water 

£>atolite   (64). 

H2Ca2B2Si2 

Vitreous. 

White 
to  gray. 

White. 

rt  ^rt 

in  closed 

P 

tube. 

Calamine  (69). 

Zn2SiO4 
-f-H2O. 

Vitreous. 

White. 

White. 

Compare  Serpentine 

and  Opal. 

tetragonal 
ledrons. 

No  water. 

Leucite  (57). 

K2Al2Si4Oi2 

Vitreous. 

White  to 
gray. 

White. 

«? 

( 

|| 

Much  water. 

Analcite  (72). 

Na2Al2Si4 

Vitreous. 

White. 

White. 

.2  '£ 

12  ~\            2^  • 

Q 

Green  to 

Very  brittle 
to  friable. 

^Apatite  (36). 

3Ca2P208 
+CaCl2. 

Vitreous. 

brown,  yel- 
low, white, 

White. 

etc. 

Squarish,  wedge- 
shaped    or 
oblique  crystals. 

Titanite   (65). 

CaTiSiO5. 

Adamantine 
to  resinous. 

Brown,  yel- 
iow,  green, 
black. 

White  to 
gray. 

NON-METALLIC    LUSTRE. 


H. 

5* 

Tenacity. 

G. 

Form. 

Cleavage. 

Other 
Properties. 

Confirmatory  Chemical  Tests. 

Tough. 

2.8 

V.  Tabular 
or  bladed 
to  fibrous 

Distinct. 

Translucent 

Fusible;   gelatinizes  with  HC1. 

5- 

Brittle. 

3-4 

V.  Some- 
times bladec 
or  fibrous. 

Prismatic, 
perfect. 

Translucent 

Fusible;   insoluble. 

V.  Usually 

5- 

Brittle  to 
flexible. 

3-2 

bladed,  fi- 
brous or 
asbestiform. 

Prismatic, 
perfect. 

Translucent. 

Fusible;   insoluble. 

5- 

Brittle  to 
flexible. 

3-1 

V.  Usually 
bladed,  fi- 
brous or 
asbestiform. 

Prismatic, 
perfect. 

Translucent. 

Fusible;    insoluble. 

5- 

Brittle. 

2.7 

V.  Acicular 
or  fibrous 
and   radiate. 

Orthopin- 
acoidal, 
perfect. 

Translucent 
to  opaque. 

Fuses;      yields    water;     gelatinizes 
with  HC1. 

5-25 

Brittle. 

2.4 

IV.  Acicular 

and  radiate 
also  massive. 

Macropin- 
acoidal, 
distinct. 

Translucent. 
Pyroelectric. 

Fuses    with    intumescence;     yields 
water;   gelatinizes  with  HC1. 

5-25 

Brittle. 

2.2 

IV.  Acicular 
'  or  fibrous 
and    radiate. 

Prismatic, 
perfect. 

Transparent 
to 
translucent. 

Fuses;      yields     water;    gelatinizes 
with  HC1. 

5- 

Tough. 

3- 

V.  Compact. 

None. 

Translucent. 

Fusible;   insoluble. 

5- 

5-5 

Tough. 

2.8 

V.  Compact. 

None. 

Translucent. 

Fuses;   gelatinizes  with  HC1. 

Brittle. 

2.9 

V.  Globular 
and  com- 
pact. 

None. 

Translucent 
to  opaque. 

Fuses  with  intumescence  and  colors 
flame  bright  green;  much  water; 
gelatinizes  with  HC1. 

4-75 

Brittle. 

3.6 

IV.  Also 
botryoidal 
and  massive. 

Prismatic, 
perfect. 

Translucent. 

Infusible;  yields  water;  green  color 
with  cobalt  solution;    gelatinizes 
with  HC1. 

5-5 

Brittle. 

2-5 

I.  Rarely 
massive. 

None. 

Translucent 
to  opaque. 

Infusible;   blue    color    with    cobalt 
solution. 

5-25 

Brittle. 

2.25 

I.  Rarely 
massive. 

Cubic,  in       Transparent 
traces.     to  opaque. 

Fuses;      yields    water;      gelatinizes 
with  HC1. 

5- 

Very  brittle. 

3-i 

III.  Prisms 
and  massive 
or   granular. 

Basal, 
imperfect. 

Transparent 
to  opaque, 

Fuses  with  difficulty;    reaction    for 
phosphorus     with       magnesium; 
soluble  in  acid. 

5- 

Brittle. 

3-5 

V.  Crystals 
and  cleav- 
able  massive. 

Prismatic. 

Translucent 
to  opaque. 

Fuses  with  intumescence. 

72 


B.     MINERALS  WITH 


Analytical    Key. 

Species.             Composition.        Lustre. 

Color. 

Streak. 

Octahedral 

i 

White, 

cleavage. 
Cubic 

Fluorite  (18). 

CaF2. 

ir-A.                   green,  violet  ,,T,  ., 
Vitreous.        ^  blue,  yel-|Whlte' 

crystals. 

low,  etc.' 

bfl 

1 

3 

Sodalite   (57). 

3Na2Al2Si2 
08-h2NaCl. 

Vitreous  to 
greasy.; 

green,  white, 
yellow,  etc. 

White. 

1 

Gelatinizes 
with  HC1. 

Nephelite   (59). 

Na2Al2Si2 
08. 

Vitreous  to 
greasy. 

White  to 
gray    or 
yellow. 

White. 

6JD 

C      . 

§2 

Wollastonite 

CaSiC)3. 

Vitreous. 

White. 

White. 

OJ  ^— 

(47)- 

^  £ 

Fuses  easily 
with  intu- 
mescence. 

Wernerite  (58). 

CaAl2Si2O8. 

Vitreous. 

White,  gray, 
reddish,  etc. 

White. 

(U    c3 

1 

J* 

Crystals  and 
cleavage 

Enstatite  (47). 

MgSiO3. 

Vitreous  to 
pearly. 

Grayish  and'    _. 
greenish    to|Whlte  to 
brown.                §rav- 

s 

v, 

prismatic 

a 

1 

a 

ntinued. 

stalline  c 

and  rectang- 
ular. 

Pyroxene   (47). 

(CaMgAl 
Fe)SiO3 

Vitreous. 

Green  to 
gray,  brown, 
black,  white. 

White  to 
greenish 
gray. 

0 

s 

f 
•« 

o 

U 

Crystals  and 
cleavage 
prismatic 
and  oblique. 

Amphibole  (49). 

(CaMgAl 
•  Fe)Si()3 

Vitreous. 

Green  to 
white,   gray, 
brown, 

black, 

White  to 
greenish 
gray. 

1 

£ 

f 

0 

bfl 

Effervesces 
and 
gelatinizes 
with  HC1. 

Cancrinite   (59). 

Na2ALSi2O8 
+H20 
and  COo 

Vitreous. 

|  White,  gray, 
yellow,    red, 
blue,  etc. 

White. 

GQ 

i! 

0 

'XTO   AT  c;  . 

W7hite  to 

K\ 

1 

Gelatinizes 
with  HC1. 

Gmelinite  (73). 

012'4-6H2O 

Vitreous. 

greenish, 
reddish,  etc. 

White. 

o 

Fuses  easily. 

J?l 

G.  below    3. 

Datolite   (64). 

HoCa2B2Si2 
0,0 

Vitreous. 

White  to 
gray. 

White. 

^  T3 

Gelatinizes 
with  HC1. 
Infusible. 

Calamine   (69) 

Zn2SiO4 

Vitreous. 

White. 

White. 

-o  S 

G.  above    3. 

/ 

rt   cS 

Fuses  and 
colors  flame 
violet. 

Apophyllite 

(70). 

OC)+KF 

Vitreous  to    Wh|fe  t(\ 
pearly.     ?*"<>*«?» 

"    or  greenish. 

White. 

"o 

| 

Ul 

0 

Fuses  with 

Chabazite    (73). 

Oi5+H2O 

Vitreous. 

i  White  to 
red. 

White. 

a 

intumes- 

Crystalli 

cence. 
G.below  2.5 

Heulandite  (74). 

Compare  Stilbite. 

jCaAl2Si6O16 
I 

Vitreous  to 
pearly 

IWhite  to 
red,  gray, 
etc. 

White. 

NON-METALLIC     LUSTRE. 


73 


H. 

4- 

Tenacity. 

G. 

Form. 

1     Cleavage. 

Properties.           Confirmatory  Chemical  Tests. 

Brittle. 

3-2 

I.  Cubes, 
also  massive. 

Octahedral, 
perfect. 

Phosphores- 
cent when 
heated. 

Decrepitates;   fuses  and  gives  alka- 
line reaction;  reaction  for   fluor- 
ine with  HKSO*. 

5-5 

Brittle. 

2-3 

I.  Dodeca- 
hedrons and 
massive. 

Dodecahe- 
dral, 
distinct. 

Translucent. 

Fuses  with  intumescence;   gelatini- 
zes with  HC1. 

5-5 

Brittle. 

2.6 

III.    Usually 
cleavable    or 
massive. 

Distinct. 

Transparent 
to  opaque. 

Fusible;    gelatinizes  with  HC1. 

5- 

Brittle  to 
tough. 

2.8 

V.  Cleavable 
or  massive. 

Distinct. 

Translucent. 

Fusible;    gelatinizes  with  HC1. 

5- 

Brittle. 

2-7 

II.  Also 
cleavable 
and  massive. 

Prismatic, 
distinct. 

Transparent 
to  opaque. 

Fuses  readily,  with  intumescence. 

5-5 

Brittle. 

3-2 

IV.  Also 
massive  and 
lamellar. 

Prismatic, 
distinct. 

Translucent 
to  opaque. 

Infusible  and  insoluble. 

5- 

Brittle. 

3-4 

V.  Often 
massive  and 
granular. 

Prismatic, 
perfect. 

Translucent 
to  opaque. 

Fusible;   insoluble. 

5- 

Brittle. 

3-2 

V.  Often 
bladed    or 
massive. 

Prismatic, 
perfect. 

Translucent 
to  opaque. 

Fusible;  insoluble. 

5.       'Brittle. 

2-5 

III.  Usually 

massive. 

Prismatic. 

Translucent. 

Fuses    with    intumescence;     yields 
water;  effervesces  and  gelatinizes 
with  HC1. 

4-5 

Brittle. 

2.1 

III.  Always 
in  hexagonal 
crystals. 

Prismatic, 
perfect. 

Transparent 
to 
translucent. 

Fuses    with    intumescence;     much 
water;  gelatinizes  with  HC1. 

5-5 
5- 

Brittle. 

2-9 

V.    Glassy 

crystals. 

Basal, 
distinct. 

Translucent. 

Fuses  with  intumescence,    coloring 
flame  bright  green;  much  water; 
gelatinizes  with  HC1. 

Brittle. 

3-6 

IV.  Also 
massive  and 
granular. 

Prismatic, 
perfect. 

Transparent 
to  opaque. 

Infusible  ;   yields  water  ;  green  color 
with  cobalt    solution;   gelatinizes 
with  HC1. 

5- 

Brittle. 

2.4 

II.  Square 
crystals,  also 
massive. 

Basal, 
perfect. 

Transparent 
to  opaque. 

Fuses    and    colors     flame     violet; 
yields  water;   reacts  for  fluorine. 

5- 

Brittle. 

2.1 

III.  Rhom- 
bohedrons. 

Rhombohe- 
dral, 
distinct. 

Transparent 
to 
translucent. 

Fuses    with    intumescence;     yields 
water. 

4- 

Brittle. 

2.2 

V.  Also 
globular  and 
granular. 

Clinopina- 
coidal, 
perfect. 

Transparent 
to  opaque. 

Fuses    with    intumescence;     yields 
water. 

B.     MINERALS     WITH 


Analytical  Key. 

Species. 

Composition. 

Lustre. 

Color. 

Streak. 

tn 

G.  6.8 

Cassiterite  (26). 

SnO2. 

Adamantine. 

Brown  to 
black  and 

Gray  to 
white. 

|5 

grav. 

^ 

0 

o 

e 

Rutile  (26). 

TiO2. 

Adamantine. 

Brown  to 
red. 

Gray  to 
brown. 

| 

J2 

*§.:       sj 

G.  4.2 

Brookite   (27). 

TiO2. 

Adamantine. 

Brown  to 
yellowish 

White  to 

"ri 

and  reddish. 

gray. 

tn 

Garnet  (53). 

Complex 
silicate. 

Vitreous. 

All  colors, 
often  bright. 

White  to 
gray. 

S 

N 

Epidote  (55). 

HoCa4FeAl2 
Si6026. 

Vitreous. 

Yellowish 
green  to 
dark  brown. 

Gray  to 
white. 

n-j 

\  ellowish 

| 

3 

0 

and    brown- 
ish green 
to    dark 
brown. 

Vesuvianite 

(54). 

(CaMg)8 

(AlFe)4Si7 
028. 

Vitreous. 

Brown  to 
green. 

White  to 
gray. 

1 
1 

umnar 

Tourmaline 

(62). 

Compare    Pyroxene 

Complex 
silicate. 

Vitreous. 

Black,  red, 
green,    blue, 
etc 

White  to 
gray. 

\ 

^ 

o 

0 

and   Amphibole. 

! 

$. 

C 

I 

.2 

o 

Diaspore   (29). 

A1203 
-hH20. 

Pearly  to 
vitreous. 

White  to 
gray  and 
brown. 

White. 

•"§       >fc 

5 

•S 

OH 

White,  gray, 
ight  brown, 

Cyanite   (63). 

Al2SiO5. 

Vitreous  to 
pearly. 

Blue  to 
white,  green 
and    gray. 

White. 

hO 

blue,    red- 

. 

"ta 

dish,  etc. 

Brown  to 

^ 

S 

Fibrolite  (63). 

Al2SiO5. 

Vitreous. 

gray,    white, 

Wrhite. 

£ 

tn 

<U 
N 

green,  etc. 

! 

Zoisite  (55). 
Compare   Pyroxene 
and  Amphibole. 

H2Ca4Al6 
Si6026. 

Vitreous  to 
pearly. 

Gray, 
brown, 
green,  red. 

White. 

Quartz  (Chalced- 
ony, Carnelian, 
Chrysoprase, 

SiO2. 

Waxy. 

White  gray 
brown,  red, 

White. 

«  rt1 

etc.)   (33)- 

green,  etc. 

2  > 

Same,  but 

^g 

Not  easily 
or  distinctly 

Quartz  (Agate, 
Onyx,  etc.)    (33). 

SiO2. 

Waxy. 

banded, 
clouded,  or 
dendritic. 

White. 

•£  6 

scratched 

Red,   brown, 

Ji  **" 

si 

by  vitreous 
quartz. 

Quartz   (Jasper, 

etc.)    (33). 

SiO2. 

Waxy  to 
dull. 

yellow, 
green,  black, 
etc. 

WThite  to 
gray. 

j& 

Quartz  (Flint, 
Chert,  etc.)  (33). 

SiO2. 

Waxy  to 
dull. 

Gray,  brown, 
black. 

White  to 
gray. 

Compare   Vitreous 

and  Milky  Quartz. 

NON-METALLIC  LUSTRE. 


75 


H.        Tenacity. 

G. 

Form. 

Other 
Cleavage.        Properties. 

Confirmatory  Chemical   Tests. 

II.  Square 

1 
6.5     Brittle. 

6.8 

prisms,    bot- 
ryoidal  and 

T    ,.    .             Translucent 
Indistinct.         to  opaque> 

Infusible  and  insoluble;     tin    with 
soda  on  charcoal. 

massive. 

6.3 

Brittle. 

4.2 

II.  Usually 
in  twins. 

Prismatic, 
distinct. 

Translucent 
to  opaque. 

Infusible  and  insoluble. 

IV.  Small 

6. 

Brittle. 

4.2 

square    crys- 

Imperfect. 

Translucent. 

Infusible  and  insoluble. 

tals. 

6-5 

Brittle. 

4.2 

I.  Crystals, 
rarely  mas-' 
sive. 

None. 

Transparent 
to  opaque. 

Fusible,     usually     to     a    magnetic 
globule;  insoluble. 

6.5 

Brittle, 

3-4 

V.   Crystals 
usually  six- 
sided. 

Orthopina- 
coidal, 
perfect. 

Transparent 
to  opaque. 

Fuses  with  intumescence  to  a  mag- 
netic mass. 

II.  Square 

6-5 

Brittle. 

3-4 

prisms,  often 

Indistinct. 

Translucent. 

Fuses  with  intumescence. 

divergent. 

7- 

Brittle. 

3-i 

III.  Rarely 
massive. 

None. 

Transparent 
to  opaque. 

Mostly  infusible;   insoluble. 

6.5 

Brittle. 

3-4 

IV.   Usually 
bladed    or 

Brachypina- 
coidal, 

Translucent. 

Infusible;      decrepitates     strongly; 
blue  color  with  cobalt  solution; 

foliated. 

perfect. 

insoluble. 

7- 

Brittle. 

3-6 

VI.  Coarsely 
bladed. 

Pinacoidal, 
distinct. 

Translucent. 

Infusible  and  insoluble;   blue  color 
with  cobalt  solution. 

V.  Usually 

Orthopina- 

6-5 

Brittle. 

3-2 

bladed  or 

coidal, 

Translucent. 

Like  cyanite. 

fibrous. 

perfect. 

IV.  Slender 

Brachypina- 

6-5 

Brittle. 

3-3 

and  deeply         coidal, 

Translucent. 

Fuses  with  intumescence. 

striated.            perfect. 

III.  Botry- 

Infusible;   insoluble;  dissolves  with 

7- 

Brittle.      c' 

2.6 

oidal,  stalac- 

Conchoidal. 

Translucent. 

effervescence  in  soda  on  platinum 

titic,  etc. 

wire. 

III.   Botry- 

7- 

Brittle. 

2.6 

oidal,  geo- 

Conchoidal. 

Translucent. 

Like  chalcedony. 

ditic,  etc. 

III.  Com- 

7- 

Brittle. 

2.6 

pact,  band- 

Conchoidal. 

Opaque. 

Like  chalcedony. 

ed,  etc. 

7- 

Brittle. 

2.6 

III.   Usually 
in    irregular 
nodules. 

Conchoidal. 

Translucent 
to  opaque. 

Like  chalcedony. 

76 


B.     MINER  ALS     WITH 


Analytical  Key. 

Species. 

Composition. 

Lustre. 

Color.               Streak. 

Turquois   (38). 

\l2P2On 

Waxy  to 
dull. 

Sky-blue  to  White  to 
apple-green.        greenish. 

-d 
V 

•3 

Bright   blue. 

•~ 

Lapis    Lazuli 

(CaNaAl)2 

Vitreous. 

Blue. 

Blue. 

O 

(57)- 

Compare  Laznhte. 

SiO4. 

1 

i 

Epidote  (55). 

H2Ca4FeAl2 
Si6O26. 

Vitreous. 

Yellowish 
green. 

Gray. 

u 

Green. 

o 

Amphibole  (49). 
(Jade  and  Neph- 
rite). 

(CaMgFe) 
SiO3. 

Vitreous. 

Deep   green 
to  greenish 
white. 

Greenish  to 
white. 

2, 

Compare  Chrysolite. 

••> 

rystallin 

Water  in 
closed  tube. 

G.   2.1 

Opal  (34). 

SiO2+H2O. 

Vitreous 
to  pearly. 

Various 
colors. 

White. 

Red  to 

Red  and 

| 

^ 

brown. 
Weathers 

Rhodonite  (48). 

MnSiOg. 

Vitreous. 

brown  to 

White. 

•c» 

black.  G.  3.5 

gray. 

1 

o 

Yellow  and 

\ 

i 

S3 

1 

-J3 

Yellow  to 

Chondrodite 

(  f\f  \ 

Mg8Si3014. 

Vitreous 
to  resinous. 

brown     to 
red    and 

W7hite  to 
gray. 

8 

o 

gray,  brown, 

(01). 

green.; 

0 

T 
r 

c 
O 

JR 
* 

"t; 
i 

etc. 
G.  above  3. 

Zoisite  (55). 

H2Ca4Al6 

Si6026. 

Vitreous 
to  dull. 

Gray  to 
brown  and 
green. 

White  to 
gray. 

.-1 

4 

8 

0 

Many  colors. 

g  *> 

"« 

U 

Weathers 

Feldspar  family 

See  next 

Vitreous 

Various 

White  Jo 

^ 

white. 

(60). 

table. 

to  dull. 

colors. 

gray. 

§ 

^5 

G.    below  3. 

J 

< 

\ 

Leucite  (57). 

K2Al2Si4Oi2. 

Vitreous. 

White  to 
gray. 

White. 

Crystals 

distinctly 

isometric. 

Garnet  (53). 

Complex 
silicate. 

Vitreous. 

All  colors, 
often  bright. 

White  to 
gray. 

cle'avabh 

Crystals 
hexagonal 
prisms  and 
pyramids. 

Quartz  (Ame- 
thyst, Smoky, 
Ferruginous,  etc.) 
(33)- 

Si02. 

Vitreous. 

Colorless, 
purple, 
yellow, 
brown,  etc. 

White. 

0 

.^ 

Tourmaline 

(62). 

Complex 
silicate. 

Vitreous. 

Black,  red, 
green,    blue, 
etc. 

White  to 
gray. 

£ 

Crystals  dis- 

S 

tinctly    pris- 
matic and 
approximate- 

Epidote (55). 

H2Ca4FeAl2 
SiO6O26. 

Vitreous. 

Yellow  ish 
green  to 
dark  brown. 

Gray  to 
white. 

ly  hexagonal 

or  triangular 

Staurolite  (66). 

MgFe2Al12 
Si6O34. 

Vitreons  to 
resinous. 

Dark  brown 
to  black. 

Gray  to 
white. 

NON-METALLIC  LUSTRE. 


77 


H. 

Tenacity. 

G. 

Form. 

Cleavage. 

Other 
Properties. 

Confirmatory  Chemical  Tests. 

6. 

Brittle. 

2.7 

Amorphous, 
incrusting. 

Sone. 

Opaque. 

Infusible;     but    yields    water    and 
turns  brown;   soluble  in  HC1. 

6.5 

Brittle. 

2,4 

I.  Usually 
compact. 

None. 

Opaque. 

Fusible;   gelatinizes  with  HC1. 

6.5 

Brittle. 

3-4 

V.  Compact 
to  finely 
granular. 

None. 

Opaque. 

Fuses  with  intumescence  to  a  mag- 
netic mass. 

6. 

Tough. 

3-2 

V.  Compact. 

None. 

Translucent. 

Fusible;   insoluble. 

6. 

Brittle. 

2.1 

Amorphous. 

None. 

Transparent 
vto 
translucent. 

Infusible;   water  in  closed  tube. 

6.5 

Tough. 

3-5 

VI.  Compact 
or  massive. 

Indistinct. 

Translucent 
to  opaque. 

Fusible;     amethystine     bead     with 
borax. 

'6-5 

Brittle. 

3-2 

V.  Usually 
in  rounded 
grains. 

None. 

Translucent 
to  opaque. 

Infusible;   gelatinizes  with  HC1. 

6-5 

Brittle. 

3-3 

IV.  Compact 
to   hnely 
crystalline. 

None. 

Translucent 
to  opaque. 

Swells  up  and  fuses. 

6.5 

Brittle. 

2-7 

V.  and  VI. 

Compact 
and  porphy- 
ritic. 

None. 

Opaque. 

Fuses    with    difficult}7;     insoluble; 
weathers  white. 

6. 

Brittle. 

2-5 

I.  Crystals, 
rarely 
massive. 

None. 

Translucent 
to  opaque. 

Infusible;   blue     color    with  cobalt 
solution;   insoluble. 

6-5 

Brittle. 

3-2 

I.  Crystals, 
rarely 
masive. 

None. 

Transparent 
to  opaque. 

Fusible,    usually     to    a     magnetic 
globule;   insoluble. 

7- 

Brittle. 

2.6 

III.  Prisms 
and 
pyramids. 

None. 

Transparent 
to  opaque. 

Infusible;   insoluble;  dissolves  with 
effervescence  in    soda    on    plat- 
inum wire. 

7- 

Brittle. 

3-i 

III.  Usually 
triangular 
prisms. 

None. 

Transparent 
to  opaque. 

Mostly  infusible;   insoluble. 

6-5 

Brittle. 

3-4 

V.  Crystals 
usually  six- 
sided. 

Orthopina- 
coidal, 
perfect. 

Transparent 
to  opaque. 

Fuses  with  intumescence  to  a  black, 
magnetic  mass. 

7- 

Brittle. 

3-6 

IV.  Usually 
in  cruciform 

twins. 

Imperfect. 

Translucent 
to  opaque. 

Infusible  and  insoluble. 

78 


B.     MINERALS  WITH 


Analytical    Key.                           Species.              Composition.        Lustre.                Color. 

Streak. 

\ 

Wernerite   (^)- 

CaAl2Si2O8. 

Vitreous          White   gray, 
reddish,  etc.! 

White. 

Crystals  dis- 

tinctly pris- 
matic and 
approximate- 

Vesuvianite 

(54)- 

(CaMg)8 
(AlFe)4Si7 

Oo8. 

Vitreous. 

Brown  to 
green. 

White  to 
gray. 

ly  square  or 

octagonal. 

Andalusite  (63). 

Vitreous  to 
rln  11 

White,  gray, 
red,   green, 

White  to 

brown.               Kra-y- 

Crystals  dis- 
tinctly   pris- 
matic  and 

Zoisite  (55). 

H2Ca4Al6 
Si6O26. 

\ 
Gray,  to 
Vitreous.              brown, 
green  to  red. 

\Vhite. 

bio 

~ 
'o 

not    belong- 
ing to  the 
foregoing. 

Spodumene 

W- 

Li6Al8 
Sii5O45. 

Vitreous  to 
pearly. 

White  to 
gray  and 
green. 

White. 

* 

<u 
v 

Blue. 

Lazulite   (38). 

MgAlP209 
+H2O. 

Vitreous. 

Blue. 

White. 

1 

| 

^s 

8 
.P 

1 

1 

tJO 
G 

No  distinct 

Chrysolite   (52). 

(MgFe)2Si 

Vitreous. 

Green. 

White. 

\ 

*1 

.- 

c 

cleavage. 

4- 

SJi 

c 

g 

0 

Green  to 

L. 

\ 
$ 

ro 

( 

o 

greenish 
gray. 

Prehnite   (69). 

H2CaAl2Si3 
012. 

Vitreous. 

Green  to 

gray. 

White. 

O 

^ 

T3 

a 

1 

c 

Red  and 

it 

|* 

rO 

42 

Rhodonite  (48).  MnSiO8. 

Vitreous. 

brown  to 

White. 

^ 

, 

Cb 

> 

gray. 

i 

CJ 

CJ 

0 
0 

No  distinct 
cleavage. 
Red,  yellow 
or  brown. 

Quartz 

(Amethyst,  Rose,   ^() 
Smoky  and  Fer- 
ruginous)   (33). 

Vitreous. 

Purple,    red, 
v  el  low, 
brown,  etc. 

\Vhite. 

Crystall 

Chondrodite          Ar     ,,.  ^ 
(6l)  |Mg8Si3014. 

Vitreous  to 
resinous. 

Yellow,  red, 
brown,    to 
greenish. 

White. 

No  cleavage. 
White  or 
colorless. 

Quartz  (Vitreous, 
Milky,  etc.)    (33). 

Si02. 

Vitreous. 

All  colors 
and  color- 
less. 

White. 

Cleavable 
obliquely. 
G.   above  3. 

Spodumene          Li6Al8Sii5 
(48).                045. 

Vitreous  to 
pearly. 

White  to 
gray  and 
green 

White. 

!  • 

Cleavable  at 
right  angles. 

iXlOrthoclase 

'"              and 
£,  Albite. 

tfi 

;K2Al2Sie 
016. 
Na2Al2Si6 

Vitreous  to 
pearly. 

White  to 
gray,  red, 
green,  etc 

White. 

G.   below  3. 

£    Oligc^clase      (Na2Ca)Al2 
&           and                      SifiOu. 
2    Labradorite.  !(Na2Ca)Al2 
4>     Compare    Neph-              SLOm 

Vitreous  to 
pearly. 

White,    gray 
to  greenish 
and  reddish. 

White. 

"            elite  and 

_. 

ll'crnerite 

NON-METALLIC    LUSTRE. 


79 


H. 

Tenacity.         G.           Form.            Cleavage. 

Other 
Properties. 

Confirmatory  Chemical  Tests. 

6. 
6.5 

6. 

Brittle. 
Brittle. 
Brittle. 

2.7 
3-4 

3-2 

II.  Also 
cleavable 
and  massive. 

II.  Often 
irregular  and 
divergent. 
IV.  Usually 
black  square 
or  cross    on 
section. 

Prismatic, 
distinct. 

Indistinct. 
Imperfect. 

Transparent 
to  opaque. 

Translucent. 

Transparent 
to  opaque. 

Fuses  readily  with  intumescence. 
Fuses  with  intumescence. 
Infusible  and  insoluble. 

6.5 

Brittle. 

3-3 

IV.    Slender 
prisms  deep- 
ly striated. 

Brachypin- 
acoidal, 
perfect. 

Translucent. 

Fuses  with  intumescence. 

6.75 
6. 

Brittle. 

3-2 

V.     Large 
broad 

crystals. 

Prismatic, 
perfect. 

Transparent 
to  opaque. 

Fuses  with  reddish  flame   and    in- 
tumescence. 

Brittle. 

V.  Octahe- 
drons, also 
massive. 

Imperfect. 

Opaque. 

Whitens  and    yields    water;     blue 
color  is  restored  by  cobalt 
solution. 

6.5 

Brittle. 

34 

IV.    Usually 
in  grains  or 
granular. 

Conchoidal. 

Translucent. 

Infusible;   gelatinizes  with  HC1. 

6.5 

Brittle. 

2.9 

IV.  Often 
with  crested 
surface. 

Basal, 
indistinct. 

Translucent. 

Fusible  with  intumescence;    yields 
water. 

6.5 

Tough. 

3-5 

Compact  to 
finely  crys- 
talline. 

None. 

Translucent 
to  opaque. 

Fusible;      amethystine    bead    -with 
borax. 

7- 

Brittle. 

2.6 

III.  Prisms, 
pyramids 
and  massive. 

Conchoidal. 

Transparent 
to  opaque. 

Infusible;   insoluble;    dissolves  with 
effervescence  in    soda     on    plat- 
inum wire. 

6-5 

Brittle. 

3-2 

V.  Usually 
in  rounded 
grains. 

None. 

Translucent 
to  opaque. 

Infusible;   gelatinizes  with  HC1. 

7- 

Brittle. 

2.6 

III.  Prisms, 

pyranids  and 
massive. 

Conchoidal. 

Infusible;    insoluble;  dissolves  with 
Transparent  j      effervescence  in    soda    on       lat. 
to  opaque.      inum  ^^ 

6.75 

Brittle. 

3-2 

V.  Prisms 
and    cleava- 
ble   masses. 

Prismatic, 
perfect. 

Translucent   Fuses  with  reddish  flame    and   in- 
to opaque.       tumescence. 

6.5 

Brittle. 

2.6 

V.  and  VI. 

Often 
massive. 

Basal   and 
clinopina- 
coidal,  per- 
fect. 

Transparent 
to 
translucent. 

Fusible  with  difficulty;  insoluble. 

6-5 

Brittle. 

2.7 

VI.  Usually 
massive  . 

Like  ortho- 
clase. 

Transparent 
to 
translucent. 

Fusible  with  difficulty;   insoluble. 

8o 


B.     MINERALS    WITH 


Analytical  Key. 

Species. 

I 
Composition.1       Lustre. 

Color. 

Streak. 

||  F  Streak  White  or  Gray.—  Continued. 

||  5.  Adamantine. 

00 

.^ 

•8 

Is 
s 

d 

E* 

Isometric. 

Diamond  (5). 

C. 

Adamantine, 
brilliant. 

Colorless  to 
yellowish, 
reddish,  etc. 

White. 

W 

Hexagonal. 

Corundum  (25). 

Compare  Emery, 

A1203. 

Vitreous. 

Gray,  brown, 
red,    yellow,!,  „  . 
blue,    black,|  Whlte' 

etc.' 

00 

8 

Orthorhom- 
bic. 

Chrysoberyl 

(24)- 

BeAl2O4. 

Vitreous. 

Green. 

White. 

is 

|  8 

Black  to  red. 

Spinel  (23). 

MgAl204. 

Vitreous. 

Black,  red, 
blue,    green, 
yellow,  etc. 

White. 

Dodecahe- 
drons and 
tetrag. 
trisoct 

Chiefly    red, 
yellow    or 
brown. 

Garnet  (53). 

1 

Complex 
silicate. 

Vitreous. 

All  colors, 
often  bright. 

White. 

Square  prisms  and 
pyramids. 

Adamantiry; 
usually/ 

bright. 

Zircon  (26). 

ZrSi04. 

Adamantine. 

Gray,   ye'l- 
lowish, 
brownish, 
etc. 

White. 

Vitreous, 
usually 
weak. 

Andalusite(63). 

Al2SiO6. 

Vitreous  to 
dull. 

White,  gray, 
red,  green, 
brown. 

White. 

Triangular 
prisms  anc 
rhombohe- 
drons. 

Chiefly 
'black. 

Tourmaline 

(62). 

Complex 
silicate. 

Vitreous. 

Black,  red,    whi      t 
green,   blue, 

etc.j 

Rhombic  prisms. 

Perfect   ba- 
sal cleavage. 

Topaz  (64). 

Al2SiO4F2. 

Vitreous. 

Yellow, 
white,  green, 
blue,  red, 
etc. 

White. 

Nio  basal 
cleavage. 

Staurolite  (66). 

MgFe2Ali2 
Si6034. 

Vitreous  to 
resinous. 

Dark  brown 
to  black. 

White  to 
gray. 

Hexagonal  prisms 
or  pyramids. 

Green. 

Beryl  (50). 

Compare  Epidote. 

Be3Al2Sie 
018. 

Vitreous. 

Green  to 
yellow  and  j  White, 
white. 

Various 
colors. 

Quartz 

(Amethyst, 
Smoky,  Ferru- 
ginous, etc.)  (33). 

Si02. 

Vitreous. 

Colorless, 
purple,    yel- 
low, brown, 
etc. 

White. 

t>  i-g  -^ 

Blue  to 
gray,  etc. 

Cyanite  (63). 

Compare  Fibrolite, 
Diaspore,   Topaz- 

Al2SiO6. 

Vitreous  to 
pearly. 

Blue  to 
white,  green 
and    gray. 

White. 

1 

Green. 

i/ 

Chrysolite  (52). 

(MgFe)2 
SiO4. 

Vitreous. 

Green. 

White. 

Brown  to 
black. 

Cassiterite  (26). 

SnO2. 

Adamantine. 

Brown  to 
black,  etc. 

White  to 
gray. 

NON-METALLIC  LUSTRE. 


81 


H. 

10. 

Tenacity.          G. 

Form. 

Cleavage. 

Other 
Properties. 

Confirmatory  Chemical   Tests. 

Brittle. 

|l.  Usually 
3.5     with    curvec 
faces 

Octahedral, 
perfect 

[Transparent 

Burns  at  a  high  temperature;     in- 
soluble. 

9- 

Brittle  to 
tough. 

4- 

III.  Also         ^       .         . 
massive  to  |Basal  ™<l 
finely  granu-   rhombohe- 
lar.                draL 

Transparent 
to  opaque 

Infusible  and  insoluble. 

8.5 

Brittle. 

3-7 

IV.  Usually 
in  hexagonal 
twins. 

Imperfect. 

Transparent 
to 
translucent. 

Infusible  and  insoluble. 

8. 

Brittle. 

3-8 

I.  Octahe- 
drons and 
water-worn 
grains. 

Octahedral. 

Transparent 
to  opaque. 

[nfusible  and  insoluble. 

7-5 

Brittle. 

3-2 

to 
4-3 

I.  Distinct 
crystals, 
rarely   gran- 
ular. 

Imperfect. 

Transparent 
to  opaque. 

Fusible,     usually     to     a    magnetic 
globule;   insoluble. 

7-5 

Brittle. 

4-4 

II.   Rarely 
irregular 
grains. 

Imperfect. 

Transparent 
to  opaque. 

Infusible  and  insoluble. 

7-5 

Brittle. 

3-2 

IV.  Usually  a 
black  square 
or  cross  on 
section. 

Imperfect. 

Transparent 
to  opaque. 

[nfusible  and  insoluble. 

7-5 

Brittle. 

3-i 

III.  Rarely 
massive. 

None. 

Transparent 
to  opaque. 

Mostly  infusible;   insoluble. 

8. 

Brittle. 

3-5 

IV.  Rarely 
massive  or 
granular. 

Basal, 
perfect. 

Transparent 
to    opaque. 

'nfusible  and  insoluble;   blue  color 
with  cobalt  solution;   fluorine  re- 
action. 

7-25 

Brittle. 

3-6 
2-7 

IV.  Usually 
in  cruciform 
twins. 

Imperfect. 

Translucent 
to   opaque. 

infusible  and  insoluble. 

8. 

7- 

Brittle. 

III.  Rarely 
massive. 

Imperfect. 

Transparent 
to 
translucent. 

nfusible  and  insoluble. 

Brittle. 

2.6 

III.   Prisms 
and  pyra- 
mids. 

None. 

Transparent 
to  opaque. 

infusible;  insoluble;  dissolves  with 
effervescence  in  soda    on    plati- 
num wire. 

• 

7.25   brittle. 

3.6 

VI.  Coarsely 
bladed. 

Pinacoidal, 
distinct. 

Translucent.1 

nfusible;  insoluble;  blue  color  with 
cobalt  solution. 

7- 

Brittle. 

3-4 

IV.  Usually 
in  grains 
or  granular. 

Conchoidal. 

Translucent.  Infusible;    gelatinizes  with  HC1. 

* 

Brittle. 

6.8 

II.  Square 
prisms,    bot- 
ryoidal    and 
massive. 

Indistinct. 

Translucent  1 
to  opaque. 

Infusible;   insoluble;   tin  with  soda 
on  charcoal. 

HOW    TO    USE    THE    TABLES. 


The  plan  of  these  Tables,  and  the  method  of  using  them  in  determining  minerals, 
have  been  explained  incidentally  in  the  Introduction ;  but  a  more  connected 
statement  will  probably  be  useful  to  many  students.  Minerals  are  divided  at  the 
outset  into  two  great  classes,  metallic  and  non-metallic.  Each  class  comprises 
five  subclasses,  the  metallic  subclasses  being  distinguished  according  to  the  colors 
of  the  species,  and  the  non-metallic  subclasses  according  to  the  streaks,  or  colors 
of  the  powdered  minerals.  The  species  in  each  subclass  are  further  distinguished, 
according  to  hardness,  as  very  soft,  soft,  hard,  very  hard  and,  in  the  fifth  non- 
metallic  subclass,  adamantine.  We  thus  by  (i)  the  lustre,  (2)  the  color  or 
streak  and  (3)  the  hardness,  of  minerals  divide  them  into  forty-one  groups,  as 
shown  in  the  general  classification  on  page  25.  This  synopsis  of  the  tables  also 
obviates  the  necessity  of  continually  turning  the  pages,  as  it  enables  us  to  turn 
at  once  to  the  page  on  which  the  mineral  in  hand  is  described. 

In  the  analytical  key  on  the  left  margin  of  each  table  these  groups  are  sub- 
divided in  accordance  with  other  and  various  physical  properties,  until  we  come 
to  the  individual  species,  or  groups  of  two  or  three  species  only,  in  the  next 
column  to  the  right.  While  in  the  succeeding  columns  we  find,  besides  the 
composition,  a  concise  physical  description  of  each  species,  by -which  it  may 
be  more  carefully  distinguished  from  those  most  closely  resembling  it,  and  the 
identification  verified  ;  and,  finally,  the  broad  column  on  the  right  margin  contains 
a  brief  statement  of  the  chemical  tests,  which  are  our  last  resort,  to  be  tried 
only  when  the  determination  is  not  otherwise  satisfactory. 

To  make  the  method  of  using  the  tables  still  clearer,  a  single  example  is 
appended,  using  a  fragment  of  galenite.  Turning  to  the  general  classification  on 
page  25  ,  we  observe  first  that  it  is  metallic,  and  take  the  left  column;  next 
that  it  is  not  red,  brown,  yellow  or  *black,  but  gray,  belonging  in  the  fourth 
subclass;  and  then,  trying  the  hardness  with  steel,  find  that  it  cuts  easily  and 
is  soft;  and  turn  to  page  42  for  the  detailed  analysis  of  this  group.  Here  the 
six  species  in  this  group  are  divided  by  the  streak  into  three  subgroups,  and  on 
testing  the  specimen  it  is  found  to,  belong  to  the  second,  having  a  dark  gray 
streak.  This  subgroup  includes  three  species — stibnite.  galenite  and  chalcocite ; 
and  on  glancing  over  the  physical  descriptions  to  the  right  it  is  seen  that,  while 
they  agree  closely  in  certain  properties,  they  are  easily  distinguished  by  others, 
especially  by  color,  density,  form  and  cleavage.  If,  however,  the  specimen  is 
of  an  impure  or  doubtful  character,  fusion  on  charcoal  will  show  that  it  gives 
reactions  for  lead,  but  not  for  copper  and  antimony. 

In  all  cases  where  the  meaning  of  the  Tables  is  not  clear,  the  student  should 
refer  to  the  section  of  the  Introduction  where  the  property  or  test  is  explained. 
It  may  be  fairly  said  that  the  golden  rule  in  determinative  mineralogy  is  to 
follow  the  order  of  the  tables,  and  not  skip  about,  or  guess  at  the  names  or 
relations  of  minerals. 


INDEX. 


Actinolite,  70. 

Agate,  74. 
ixAlbite,  78.- 

Allanite,  36,  38,  68. 

Amber,  60. 

Amethyst,  76,  78,  80. 

Amphibole,  58,  68,  70,  72,  76. 

Analcite,  70. 

Andalusite,   78,  80 

Anglesite,  62. 

Anhydrite,  66. 

Antimony,  40,  46. 

Apatite,  70. 

Apophyllite,  72. 

Aragonite,  64,  72. 

Argentite,  32,  34,  40. 

Arsenic,  34,  40,  46. 

Arsenopyrite,  30,  32,  42,  44,  46. 

Asbestus,  70. 

Asphaltum,  48,  56. 

Atacamite,  58. 
>ftugite,  58,  68. 

Azurite,  58. 

Barite,  62. 

Beryl,  80. 

Biotite,  32,  34,  64. 

Bismuth,  40,  46. 

Borax,  60. 

Bornite,  28,  30. 

Brookite,  28,  36,  38,  68,  74. 

Brown  coal,  26. 

Brucite,  66. 

Calamine,  62,  70,  72. 

Calcite,  60,  64. 

Cancrinite,  72. 

Carnelian,  74. 

Cassiterite,  28,  38,  44,  52,  74,  80. 

Celestite,  62. 

Cerargyrite,  60. 

Cerussite,  62. 

Chabazite,  72. 

Chalcedony,  74. 

Chalcocite,  34,  42. 

Chalcopyrite,  30. 

Chalk,  60. 

Chert,  74.- 

Chloritoid',  68. 


Chondrodite,  76,  78. 

Chromite,  36,  44,  52. 

Chrysoberyl,  80. 

Chrysocolla,  58,  66. 

Chrysolite,  78,  80. 

Chrysoprase,  74. 

Chrysotile,  64. 

Cinnabar,  26,  48,  50. 

Clay,  60. 

Cobaltite,  42,  44,  46. 

Columbite,  36,  38,  52,  56. 

Copal,  60. 

Copper,  26. 

Corundum,  80. 

Cryolite,  66. 

Cuprite,  26,  28,  48,  50. 

Cyanite,  74,  80. 

Datolite,  70,  72. 

Deweylite,  66. 

Diamond,  80. 

Diaspore,  74. 

Dolomite,  64. 

Emery,  38,  44. 

Enstatite,  68,  72. 

Epidote,  74,  76. 

Feldspar,  76. 

Fibrolite,  74. 

Flint,  74. 

Fluorite,  66,  72. 

Franklin ite,  36,  38,  44. 

Galenite,  42. 
jXjarnet,  74,  76,  80. 

Gibbsite,  66. 

Glauconite,  58. 

Gmelinite,  72. 

Gothite,  28,  32,  38,  50,  54. 

Gold,  30. 

Graphite,  32,  40. 

Gypsum,  60. 

Halite,  64. 

Hematite,  28,  34,  36,  38,  44,  48,  50. 

Heulandite,  66,  72. 

Hornblende,  58,  68. 
^Hydromica,  64. 
•Hypersthene,  68. 

Iron,  36,  42. 

Jade,  70,  76. 


Jasper,  52,  56,  74. 

Kaolinite,  54,  56,  60. 

Labradorite,  78. 

Lapis-lazuli,  58,  76. 

Laumontite,  66. 

Lazulite,  68,  78. 

Lepidolite,  64. 

Lepidomelane,  34,  58,  64. 
j/Leucite,  70,  76. 

Limonite,  28,  32,  38,  48,  50,  54. 

Magnesite,  64,  68. 

Magpetite,  36,  38,  42,  44. 

Malachite,  58. 

Manganite,  34,*  36,  40,  42. 

Marcasite,  30,  32,  42,  44. 

Margarite,  64. 

Melaconite,  34,  40,  56. 

Menaccanite,  36,  38,  42,  44,  52,  56. 

Mercury,  46. 

Millerite,  30. 

Mimetite,  62. 

Mineral  coal,  34,  48,  56. 

Molybdenite,  32,  40. 
^/Muscovite,  60,  64. 

Natrolite,  70. 

Nephelite,  72. 

Nephrite,  70,  76. 

Niccolite,  28,  42. 
Oligoclase,  78. 

Onyx,  74. 

Opal,  60,  76. 

Orpiment,  30,  54. 

Orthoclase,  78. 

Pectolite,  70. 

Phlogopite,  26,  30,  64. 

Finite,  66. 

Prehnite,  78. 

Prochlorite,  58,  60. 

Proustite,  26,  48,  50. 

Psilomelane,  36,  38,  42,  44,  52,  56. 

Pyrargyrite,  26,  32,  34,  48,  50. 
V/P'yrite,  30,  32. 

Pyrolusite,  32,  34,  40. 

Pyromorphite,  62. 

Pyrophyllite,  60. 

Pyroxene,  58,  68,  70,  72. 

Pyrrhotite,  28,  30,  40,  42. 
t^Quartz,  52,  56,  74,  76,  78,  80. 

Realgar,  26,  48. 


Red  ochre,  48. 
Rhodochrosite,  62. 
Rhodonite,  68,  76,  78. 
Ripidolite,  58,  60,  64. 
Rutile,  28,  38,  44,  52,  74. 
Samarskite,  36,  38,  52,  56. 
Sassolite,  60. 
Sepiolite.  60,  66. 
Serpentine,  64,  66. 
Siderite,  50,  52,  54,  62. 
Silver,  46. 

Smaltite,  42,  44,  46. 
Smithsonite,  62,  68. 
Sodalite,  68,  72. 

Sphalerite,  2o>  2&,  30,  32,  34,  36,  50,  52, 
Spinel,  80.  [54,  62,  68. 

Spodumene,  78. 
Staurolite,  76,  80. 
Stephanite,  32,  34. 
Stibnite,  40,  42. 
Stilbite,  66. 
Strontianite,  62. 
Sulphur,  54. 
Talc,  60. 

Tetrahedrite,  34,  40. 
Thomsonite,  70. 
Titanite,  68,  70. 
Topaz,  80. 

Tourmaline,  74,  76,  80. 
Tremolite,  70. 
Tripolite,  60. 

Turgite,  26,  28,  36,  38,  48,  50  52. 
Turquois,  58,  76. 
Ulexite,  60. 
Vanadinite,  54,  62, 
Vesuvianite,  74,  78. 
Vivianite,  58. 
Wad,  32,  34,  48,  50,  56. 
Wavellite,  64. 
Wernerite,  72  78. 
Willemite,  68. 
Witherite,  62. 
Wolframite,  36,  52,  56. 
Wollastonite,  70,  72. 
Wulfenite,  54,  62. 
Yellow  ochre,  48,  54. 
Zincite,  26,  28,  30,  32,  48,  50,  54. 
/Zircon,  80. 

oisite,  74,  76,  78. 


I 


BOSTON  SOCIETY  OF  NATURAL  HISTORY. 

TEACHERS'     SCHOOL     OF    SCIENCE. 


MINERALOGICAL  AND  GEOLOGICAL 

SPECIMENS  AND  COLLECTIONS. 

PREPARED  FOR  THE  USE  OF  TEACHERS  AND  STUDENTS. 

It  is  now  generally  recogonized  by  the  best  teachers  that  satisfactory  results 
in  the  study  of  natural  science  can  only  be  attained  by  the  liberal  use  of  speci- 
mens ;  and  unquestionably  the  difficulty  and  expense  of  obtaining  suitable  material 
has  been  a  great  obstacle  to  the  introduction  of  the  natural  or  scientific  method. 
The  vital  importance  of  this  matter  to  the  interests  of  sound  education  is  fully 
appreciated  by  Prof.  Alpheus  Hyatt,  of  the  Teachers'  School  of  Science ;  and 
with  his  aid  and  encouragement  the  collections  described  below  have  been  pre- 
pared for  the  express  purpose  of  supplying  schools,  teachers  and  students  with 
carefully  selected  educational  material  at  the  minimum  cost. 


ELEMENTARY  MINERALOGY. 

These  collections  are  designed  to  illustrate  Science  Guide    No.    xm.     ("First    Lessons    in 
Minerals,"  by  Ellen  H.  Richards). 

Collection  No.   I  includes  the  twenty  principal  elements  and  minerals  of  which  it  is    im- 
portant to  have  one  specimen  for  each  pupil. 

I  large  specimen  of  each  kind,  20  in  all,  labelled.         .  $  .50. 

5  smaller  specimens  of  each  kind,  100  in  all,         .         .         .    1.25. 

Collection  No.  2  includes  collection  No.  i  and    ten    additional    varieties    of    which  it    is 
desirable  to  have  at  least  one  specimen  for  every  two  or  three  pupils. 

I  large  specimen  of  each  kind,   10  in  all,  labelled,         .  $-30. 

5  smaller  specimens  of  each  kind,  50  in  all,         .         .         .         .75. 


MINERALOGY. 

The  mineral ogical  collections  may  be  used  advantageously  with    Prof.    Dana's    Manual    of 
Mineralogy,  or  Text-book  of  Mineralogy,  or  any  standard  text-book. 
Scale  of  Hardness. — Price:  Cabinet  size,  $1.00;   Student  size,  50  cents. 
Lustre  Series. —  Six  specimens  illustrating  the  principal  kinds  of  lustre. 

Price:  Cabinet  size,  $1.00. 

Cleavage  Series. — Ten  specimens  illustrating  the  principal  kinds  of  cleavage  in    the    different 
systems  of  crystallization.     Price :  Cabinet  size,   1 .50. 
Descriptive  Mineralogy  Series. — 

50  specimens.  100  specimens.  150  specimens. 

Cabinet  size,         ....  $6.00.  $15.00  #3O-°o. 

Student  size, 2.00.  5.00  10.00. 


Miniature  Mineral  Collections  in  neat,  covered  paste-board  boxes  or  trays. 
These  minerals  are  selected  from  the  choicest  materials  to  be  had,  and  with  special    refer- 
ence to  their  purity,  beauty  and  crystalline  form.     Each  specimen  is    numbered    to    correspond 
with  the  numbers  in  a  printed  list  in  the  cover  of  the  box,  and  also  with  a    descriptive    hand- 
book that  accompanies  each  collection. 

No.  i.  Twenty-five  specimens,  prepaid  by  mail,         .         .         $1.00. 
No.  2.  Fifty  specimens,  "  "       "  .         .         2.OO. 


DETERMINATIVE  MINERALOGY. 

Many  teachers  and  students  using  the  first  edition  of  the  "Tables  for  the  Determination 
of  Common  Minerals"  have  applied  for  specimens  suitable  for  practice  in  the  determination  of 
species.  To  meet  this  demand  in  the  future,  small,  but  pure  and  typical  specimens  of  most  of 
the  minerals  included  in  the  scope  of  the  "Tables"  will  be  furnished  at  an  average  price  of  3 
cents  each,  with  a  large  discount  for  duplicates. 

Pure  minerals  suitable  for  blowpipe  analysis  and  chemical  experiments  are  sold  by  weight, 
the  prices  ranging  from  5  cts.  to  50  cts.  per  pound. 


LITHOLOGY. 

The  lithological  collections  were  originally  prepared  to  illustrate  Science  Guide  No.  xn. 
(Common  Minerals  and  Rocks,  by  W.  O.  Crosby;)  but  they  have  been  recently  considerably 
extended,  and  the  larger  ones,  especially,  may  be  advantageously  used  in  connection  with  more 
advanced  text-books. 

The  prices  of  these  collections  are  as  follows: 

50  spec's.  80  spec's.     125  spec's.         150  spec's. 

Cabinet  size  with  printed  labels,         .         $2.00.  $4.00.  $8.00.  $10.00. 

Student  size, 1.25.  2.50.  5-OO.  6.00 

The  specimens  in  the  Student  collections    are  not    labelled    but  are  numbered  to  correspond 
with  the  printed  catalogue. 


ECONOMIC  MINERALOGY  AND  LITHOLOGY. 

Many  teachers  desire  to  give  special  prominence  to  those  minerals  and  rocks  having  im- 
portant uses  in  the  arts.  To  meet  this  need,  the  following  collections  have  been  arranged 
(i).  Ores. — This  collection  includes  30  typical  specimens  of  the  most  important  ores.  It 
embraces  ores  of  gold,  silver,  mercury,  copper,  lead,  zinc,  tin,  iron,  etc.  Price :  Cabinet 
size,  $5.00. 

Economic  Minerals  other  than  Ores. — This  collection  includes    45    specimens    of    minerals 
having    important  uses  in  the  arts,  but  from    which    no    metal    is    obtained,  such    as    sulphur, 
graphite,  corundum,  gypsum,  apatite,  barite,  halite,  asbestus,  etc      Price:  Cabinet  size,  $1.50. 
Collections  I  and  2  will  be  sold  together  for  $9.00;    I,  2  and  3  for  $10.00. 


STRUCTURAL  GEOLOGY  OR  PETROLOGY. 

This  collection  consists  of  30  specimens  illustrating  nearly  all  the  most  important  kinds  of 
structures  occuring  in  rocks,  as  follows:  Stratification,  Ripple-marks,  Rain-prints  Mud-cracks, 
Fossils,  Veins,  Dikes,  Stalactites,  Joints,  Cleavage,  Faults,  Folds  and  Contortions,  Concretions, 
Glacial  Striae,  etc.  Price:  Cabinet  size  $8.00. 


HISTORICAL  GEOLOGY. 

Stratigraphic  Collection. — This  includes  100  specimens  of  the  characteristic  rocks  of  the  var- 
ious geological  formations  from  the  Laurentian  to  the  Tertiary.  Price :  Cabinet  size,  $8.00. 
Paleontological  Collection. — This  embraces  50  species  (about  100  specimens') of  fossils,  select- 
ed from  the  characteristic  forms  of  the  different  formations.  Price :  Cabinet  size,  $8.00. 


APPARATUS. 

The  Apparatus  required  in  using  these  determinative  tables  will  be  furnished  as  follows:-^ 
Brass  Blowpipe,  .20;  Alcohol  lamp,  .50,  Bunsen  burner,  75;  Steel  forceps,  10;  Platinum  wird 
10;  Glass  tubes,  open,  .05  per  dozen;  closed,  .10  per  dozen;  Hammer,  anvil  and  ring,  .40; 
File,  .10;  Magnet,  .15;  Lens,  .75;  Test  tubes,  .05  each. 

AJ1  orders  should  be  addressed  to 

GEORGE  H.  BARTON, 

Boston  Society  of  Natural  History, 
Cor.  Berkeley  and  Boylston  Sts.  BOSTON,  Mass. 


\ 


UNIVERSITY  OF 


CALIFORNIA  LIBRARY 


YC  21278 


